blocks|key|2895397|text|解决这个问题非常简单：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2895398|2895399|转到控制面板。|ordered-list-item|2895400|搜索服务。|2895401|从您的搜索打开本地服务窗口。|2895402|2895403|步骤的屏幕截图：|2895404|​|2895405|📷|atomic|offset|length|2895406|2895407|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/d6d1a9507c04bef45d57bb56679c0395.png|imageAlt^0|0|0|0|0|0|0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|13|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|14|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|15|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|16|8|@]|9|@]|A|$]]|$1|H|3|I|5|E|7|17|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|18|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|19|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|1A|8|@]|9|@]|A|$]]|$1|O|3|P|5|Q|7|1B|8|@]|9|@$R|1C|S|1D|1|1E]]|A|$]]|$1|T|3|N|5|6|7|1F|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]]|V|$W|$5|X|Y|Z|A|$10|11|12|-4]]]]

Solving this problem is very easy:

<ol>
<li>Go to control panel.</li>
<li>search for services.</li>
<li>Open Local services window from your search results</li>
<li>Restart your MSSQLSERVER service.</li>
</ol>

Screenshot of the steps:

<img src="https://i.stack.imgur.com/KAcPr.png" alt="Screenshot of the steps">

blocks|key|3108532|text|最简单的解决方案--检查你的斜杠是否回来了……|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3108533|我花了大约一个小时的时间，试图弄清楚当一切都配置正确时，SERVER/INSTANCENAME出了什么问题，命名管道，用户访问权限……我突然意识到，这不是一个斜杠，而是一个反斜杠+(\)。|offset|length|style|BOLD|CODE|3108534|恐怖，羞耻..。|3108535|entityMap^0|0|S|J|2J|1|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@$D|O|E|P|F|G]|$D|Q|E|R|F|H]]|9|@]|A|$]]|$1|I|3|J|5|6|7|S|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|L|$]]

And the simplest solution - check if your slash is back... 

I spent about an hour trying to figure out what's wrong with SERVER/INSTANCENAME when everything is configured correctly, named pipes, user access rights... and suddenly it struck me, it's not a slash, it's a backslash (<code>\</code>).

The horror, the shame...

blocks|key|234397|text|在安装SQL+Server之后，实际上需要三个步骤：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|234398|234399|启用命名管道SQL配置管理器-->+SQL+Server网络配置-->协议-->命名管道-->右键单击-->重新启动|ordered-list-item|234400|234401|​|234402|📷|atomic|offset|length|234403|234404|234405|重新启动服务器SQL+Config+Manager+-->+SQL+server+Services+-->+SQL+server+(SQLEXPRESS)+-->右键单击-->重新启动|234406|使用正确的服务器和实例名称(两者都是必需的！)这通常是.\SQLEXPRESS，，例如，请参阅QueryExpress连接对话框中的屏幕截图。|style|BOLD|234407|234408|234409|234410|234411|这就对了。|234412|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/81d5a4691878ef2cd9c8b5d151e80255.png|imageAlt|1|https://ask.qcloudimg.com/http-save/yehe-900000/f668ef0f1d6d0dbee8edf376d9e63cc3.png^0|0|0|0|0|0|0|1|0|0|0|0|0|R|C|0|0|0|0|1|1|0|0|0^^$0|@$1|2|3|4|5|6|7|1C|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|1E|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|1G|8|@]|9|@]|A|$]]|$1|I|3|J|5|K|7|1H|8|@]|9|@$L|1I|M|1J|1|1K]]|A|$]]|$1|N|3|H|5|6|7|1L|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|1M|8|@]|9|@]|A|$]]|$1|P|3|Q|5|E|7|1N|8|@]|9|@]|A|$]]|$1|R|3|S|5|E|7|1O|8|@$L|1P|M|1Q|T|U]]|9|@]|A|$]]|$1|V|3|-4|5|6|7|1R|8|@]|9|@]|A|$]]|$1|W|3|H|5|6|7|1S|8|@]|9|@]|A|$]]|$1|X|3|J|5|K|7|1T|8|@]|9|@$L|1U|M|1V|1|1W]]|A|$]]|$1|Y|3|H|5|6|7|1X|8|@]|9|@]|A|$]]|$1|Z|3|10|5|6|7|1Y|8|@]|9|@]|A|$]]|$1|11|3|-4|5|6|7|1Z|8|@]|9|@]|A|$]]]|12|$13|$5|14|15|16|A|$17|18|19|-4]]|1A|$5|14|15|16|A|$17|1B|19|-4]]]]

It's a three step process really after installing SQL Server:

<ol>
<li>Enable Named Pipes
SQL Config Manager --> SQL Server Network Consif --> Protocols --> Named Pipes --> Right-click --> Restart</li>
</ol>

<a href="https://i.stack.imgur.com/Piqod.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Piqod.png" alt="named pipes enabled"></a>

<ol start="2">
<li>Restart the server
SQL Config Manager --> SQL Server Services --> SQL Server (SQLEXPRESS) --> Right-click --> Restart</li>
<li>Use proper server and instance names (both are needed!)
Typically this would be .\SQLEXPRESS, for example see the screenshot from QueryExpress connection dialog.</li>
</ol>

<a href="https://i.stack.imgur.com/7nj2W.png" rel="noreferrer"><img src="https://i.stack.imgur.com/7nj2W.png" alt="enter image description here"></a>

There you have it.

blocks|key|235850|text|我刚刚安装了SQL+SERVER+2012+developer。当我创建我的第一个SSIS包时，当我尝试在SQL+Server+2012+data+Tools中的connection+Manager框中创建数据连接任务时，收到此pipes错误。我在上面的帖子的帮助下决定了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|235851|如果选择一个命名实例，并将命名实例命名为SSQDatabase1，而您的pc名称为PCX1。您必须输入PCX1SSQDatabase1，而不仅仅是SSQDatabase1，否则将收到命名管道错误。|235852|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I had just installed SQL SERVER 2012 developer. When I was creating my first SSIS package, I received this pipes error when I was trying to create a data connection task in SQL Server 2012 Data Tools in the Connection Manager box. I resolved with the help of the post above. 

If choose a named instance and you call your named instance SSQDatabase1 and your pc's name is PCX1. You must enter PCX1\SSQDatabase1 not just SSQDatabase1
or you will receive the named pipes error.

blocks|key|2894624|text|MSDN+Social上的一个帖子，，有一个相当不错的列表，列出了与您的错误相关的可能问题。你可能想看看他们中是否有你正在经历的事情。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2894625|服务器连接字符串不正确，如using+SqlExpress|2894626|Named+Pipes(NP)未在SQL+instance|unordered-list-item|2894627|
|2894628|Remote上启用|2894629|2894630|连接未启动，或指向连接字符串中的非真实服务器|2894631|2894632|其他原因，如安全上下文不正确|2894633|2894634|尝试在您正在使用的两台计算机之间进行基本连接测试|2894635|2894636|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|Z|8|@]|9|@]|A|$]]|$1|I|3|J|5|F|7|10|8|@]|9|@]|A|$]]|$1|K|3|H|5|6|7|11|8|@]|9|@]|A|$]]|$1|L|3|M|5|F|7|12|8|@]|9|@]|A|$]]|$1|N|3|H|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|14|8|@]|9|@]|A|$]]|$1|Q|3|H|5|6|7|15|8|@]|9|@]|A|$]]|$1|R|3|S|5|F|7|16|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|17|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|V|$]]

A thread on MSDN Social, <a href="http://social.msdn.microsoft.com/forums/en-US/sqlreportingservices/thread/2a8f2e64-74cf-46f2-b2be-bbb08b1502cb/" rel="noreferrer">Re: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server</a>, has a pretty decent list of possible issues that are related to your error. You may want to see if any of them could be what you're experiencing.

<ul>
<li>Incorrect connection string, such as using SqlExpress</li>
<li>Named Pipes(NP) was not enabled on the SQL instance</li>
<li>Remote connection was not enabled</li>
<li>Server not started, or point to not a real server in your connection string</li>
<li>Other reasons such as incorrect security context</li>
<li>try basic connectivity tests between the two machines you are working on</li>
</ul>

blocks|key|233494|text|我刚刚在Sql+Server配置管理器中启用了TCP/IP，VIA，命名管道，我的问题已经解决了。有关更多信息，请参阅此Resolving+Named+Pipes+Error+40+|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|233495|entityMap|0|LINK|mutability|MUTABLE|url|https://web.archive.org/web/20151027020437/http://microsoft-sql-ssis.blogspot.in/2015/09/how-to-fix-named-pipes-provider-error.html^0|1O|V|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

i Just enabled TCP/IP,VIA,Named Pipes in Sql Server Configuration manager , My problem got solved refer this for more info <a href="https://web.archive.org/web/20151027020437/http://microsoft-sql-ssis.blogspot.in/2015/09/how-to-fix-named-pipes-provider-error.html" rel="nofollow noreferrer">Resolving Named Pipes Error 40 </a>

blocks|key|2894693|text|在我的项目中使用服务器\实例名称+.Using双反斜杠解决了我的问题。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|2894694|entityMap^0|8|8|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

Use SERVER\\ INSTANCE NAME .Using double backslash in my project solved my problem.

blocks|key|230312|text|多亏了达米安。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|230313|TCP/IP命名管道...两者均已启用|230314|Web+Config...(用于localhost)|230315|<add+name="FooData"+connectionString="Data+Source=localhost\InstanceName;Initial+Catalog=DatabaseName;Integrated+Security=True;"+providerName="System.Data.SqlClient"+/>|code-block|syntax|javascript|230316|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Thanks to Damian...

TCP/IP
Named Pipes
... both enabled

Web Config....(for localhost)

<pre><code>&lt;add name="FooData" connectionString="Data Source=localhost\InstanceName;Initial Catalog=DatabaseName;Integrated Security=True;" providerName="System.Data.SqlClient" /&gt;
</code></pre>

blocks|key|234173|text|也有同样的问题。当不得不迁移一些服务器时，我花了大约6个小时。我尝试了关于这个主题和其他主题的所有建议。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|234174|解决方案就像服务器重启一样简单！|offset|length|style|BOLD|234175|entityMap^0|0|0|G|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Did have the same problem. Spent like 6 hours when had to migrate some servers.
Tried all suggestions available on this topic and others.

Solution was as simple as server restart!

blocks|key|233227|text|非常简单的解决方案|type|unstyled|depth|inlineStyleRanges|entityRanges|data|233228|使用(local)\InstanceName就是这样。这对我很管用。|offset|length|style|CODE|233229|entityMap^0|0|2|K|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

Very simple solution 

use <code>(local)\InstanceName</code>
that's it. it worked for me.

blocks|key|3109867|text|TL;DR;您的SQL+Server实例正在使用不工作的动态端口。强制SQL+Server使用静态端口#+1433。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3109868|Complete+Details：首先，如果你混合了默认实例和命名实例，或者只有命名实例(我的情况就是这样)，那么这个问题就更有可能出现。|3109869|Key+concept：安装在计算机上的每个Microsoft+SQL+Server实例都使用不同的端口来侦听传入的连接请求。SQL+Server的默认实例使用端口#+1433。当您安装命名实例时，它们将开始使用动态端口，这是在启动与命名SQL+Server实例对应的Windows服务时决定的。|3109870|我的代码无法连接到我的虚拟机上唯一命名的SQL+Server实例(错误代码为40)。您可以尝试以下可能的解决方案：|3109871|解决方案#+1：尝试连接到SQL+Server实例的客户端代码需要SQL+Server+browser服务的帮助，以确定命名实例正在侦听传入连接的端口号。确保您的计算机上正在运行SQL+browser服务。|3109872|解决方案#+2：检查SQL+Server配置管理器中命名的SQL+Server实例正在使用的端口号(黄色)，如下面的快照所示：|3109873|​|3109874|📷|atomic|3109875|3109876|在您的连接字符串中显式使用该端口号，或者使用如下所示的sqlcmd：|CODE|3109877|sqlcmd+-s+mymachinename,11380+-i+deleteDB.sql+-o+SQLDelete.txt|code-block|syntax|javascript|3109878|解决方案#+3：强制您的命名实例使用默认实例使用的端口#+1433。请记住，只有当您的计算机上没有任何默认的SQL+Server实例时，这才会起作用，因为默认的SQL+Server实例已经在使用端口#+1433。两个不同Windows服务不能使用相同的端口号。|3109879|将TCP+Dynamic+ports字段标记为空，将TCP+Port字段标记为1433。|3109880|3109881|3109882|3109883|更改连接字符串中的端口号，如下所示：|3109884|sqlcmd+-s+mymachinename\instanceName+-i+deleteDB.sql+-o+SQLDelete.txt|3109885|或|3109886|sqlcmd+-s+mymachinename,1433+-i+deleteDB.sql+-o+SQLDelete.txt|3109887|注意：/IP设置的每次更改都需要重新启动相应的Windows服务。|3109888|有趣的是，在解决了错误之后，当我返回到动态端口设置来重现相同的错误时，它并没有发生。不知道为什么。|3109889|请阅读以下有趣的线程，以了解有关SQL+Server动态端口的更多信息：|3109890|How+to+configure+SQL+Server+Port+on+multiple+instances?|3109891|When+is+a+Dynamic+Port+“dynamic”?|3109892|When+to+use+a+TCP+dynamic+port+and+when+TCP+Port?|3109893|我从this博客上找到了我的问题的解决方案。|3109894|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/229c84d48859b10f4d8b2c77702aea55.png|imageAlt|1|https://ask.qcloudimg.com/http-save/yehe-900000/0df5f77cb126f8ffca6f0a9509f1a81f.png|2|LINK|MUTABLE|url|https://dba.stackexchange.com/q/107760/101434|3|https://dba.stackexchange.com/q/47651/101434|4|https://dba.stackexchange.com/q/220129/101434|5|https://knowledgebase.apexsql.com/configure-remote-access-connect-remote-sql-server-instance-apexsql-tools/^0|0|6|0|0|G|0|0|B|0|0|0|7|0|0|7|0|0|0|1|0|0|0|R|6|0|0|0|7|0|1|H|Q|8|0|0|0|1|1|0|0|0|0|0|1|0|0|0|3|0|0|0|0|1J|2|0|0|X|3|0|0|1D|4|0|2|4|5|0^^$0|@$1|2|3|4|5|6|7|2I|8|@$9|2J|A|2K|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|2L|8|@$9|2M|A|2N|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|2O|8|@$9|2P|A|2Q|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|2R|8|@]|D|@]|E|$]]|$1|L|3|M|5|6|7|2S|8|@$9|2T|A|2U|B|C]]|D|@]|E|$]]|$1|N|3|O|5|6|7|2V|8|@$9|2W|A|2X|B|C]]|D|@]|E|$]]|$1|P|3|Q|5|6|7|2Y|8|@]|D|@]|E|$]]|$1|R|3|S|5|T|7|2Z|8|@]|D|@$9|30|A|31|1|32]]|E|$]]|$1|U|3|Q|5|6|7|33|8|@]|D|@]|E|$]]|$1|V|3|W|5|6|7|34|8|@$9|35|A|36|B|X]]|D|@]|E|$]]|$1|Y|3|Z|5|10|7|37|8|@]|D|@]|E|$11|12]]|$1|13|3|14|5|6|7|38|8|@$9|39|A|3A|B|C]]|D|@]|E|$]]|$1|15|3|16|5|6|7|3B|8|@$9|3C|A|3D|B|X]|$9|3E|A|3F|B|X]]|D|@]|E|$]]|$1|17|3|Q|5|6|7|3G|8|@]|D|@]|E|$]]|$1|18|3|S|5|T|7|3H|8|@]|D|@$9|3I|A|3J|1|3K]]|E|$]]|$1|19|3|Q|5|6|7|3L|8|@]|D|@]|E|$]]|$1|1A|3|1B|5|6|7|3M|8|@]|D|@]|E|$]]|$1|1C|3|1D|5|10|7|3N|8|@]|D|@]|E|$11|12]]|$1|1E|3|1F|5|6|7|3O|8|@$9|3P|A|3Q|B|C]]|D|@]|E|$]]|$1|1G|3|1H|5|10|7|3R|8|@]|D|@]|E|$11|12]]|$1|1I|3|1J|5|6|7|3S|8|@$9|3T|A|3U|B|C]]|D|@]|E|$]]|$1|1K|3|1L|5|6|7|3V|8|@]|D|@]|E|$]]|$1|1M|3|1N|5|6|7|3W|8|@]|D|@]|E|$]]|$1|1O|3|1P|5|6|7|3X|8|@]|D|@$9|3Y|A|3Z|1|40]]|E|$]]|$1|1Q|3|1R|5|6|7|41|8|@]|D|@$9|42|A|43|1|44]]|E|$]]|$1|1S|3|1T|5|6|7|45|8|@]|D|@$9|46|A|47|1|48]]|E|$]]|$1|1U|3|1V|5|6|7|49|8|@]|D|@$9|4A|A|4B|1|4C]]|E|$]]|$1|1W|3|-4|5|6|7|4D|8|@]|D|@]|E|$]]]|1X|$1Y|$5|1Z|20|21|E|$22|23|24|-4]]|25|$5|1Z|20|21|E|$22|26|24|-4]]|27|$5|28|20|29|E|$2A|2B]]|2C|$5|28|20|29|E|$2A|2D]]|2E|$5|28|20|29|E|$2A|2F]]|2G|$5|28|20|29|E|$2A|2H]]]]

TL;DR; Your SQL Server instance is using dynamic ports which is not working. Force SQL Server to use static port # 1433.

Complete Details: First of all this problem is more likely if you've a mix of default and named instance or named instances only(which was my case).

Key concept: Each instance of Microsoft SQL Server installed on a computer uses a different port to listen for incoming connection requests. Default instance of SQL Server uses port # 1433. As you install named instances then they will start using dynamic ports which is decided at the time of start-up of Windows service corresponding to named SQL Server instance.

My code was failing (with error code 40) to connect to the only named SQL Server instance that I had on my VM. You can try below possible solutions:

Solution # 1: Client code trying to connect to SQL Server instance takes help from SQL Server browser service to figure out port number at which your named instance is listening for incoming connections. Make sure SQL browser service is running on your computer.

Solution # 2: Check the port # (in yellow color) your named SQL Server instance is using from SQL Server configuration manager as shown in the snapshot below: 

<a href="https://i.stack.imgur.com/NXRnj.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NXRnj.png" alt="enter image description here"></a>

Use that port number explicitly in your connection string or with <code>sqlcmd</code> shown below:

<pre><code>sqlcmd -s mymachinename,11380 -i deleteDB.sql -o SQLDelete.txt
</code></pre>

Solution # 3: Force your named instance to use port # 1433 which is used by default instance. Remember this will work only if you don't have any default SQL Server instance on your computer as the default SQL Server instance would be using using port # 1433 already. Same port number can't be uses by two different Windows services.

Mark <code>TCP Dynamic ports</code> field to blank and <code>TCP Port</code> field to 1433.

<a href="https://i.stack.imgur.com/NREO0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NREO0.png" alt="enter image description here"></a>

Change the port number in your connection string as shown below:

<pre><code>sqlcmd -s mymachinename\instanceName -i deleteDB.sql -o SQLDelete.txt
</code></pre>

OR 

<pre><code>sqlcmd -s mymachinename,1433 -i deleteDB.sql -o SQLDelete.txt
</code></pre>

Note: Every change in TCP/IP settings requires corresponding Windows service restart.

Interestingly enough after resolving the error when I went back to dynamic port setting to reproduce the same error then it didn't happen. Not sure why.

Please read below interesting threads to know more about dynamic ports of SQL Server:

<a href="https://dba.stackexchange.com/q/107760/101434">How to configure SQL Server Port on multiple instances?</a>

<a href="https://dba.stackexchange.com/q/47651/101434">When is a Dynamic Port “dynamic”?</a>

<a href="https://dba.stackexchange.com/q/220129/101434">When to use a TCP dynamic port and when TCP Port?</a>

I got leads to solution of my problem from <a href="https://knowledgebase.apexsql.com/configure-remote-access-connect-remote-sql-server-instance-apexsql-tools/" rel="nofollow noreferrer">this</a> blog.

blocks|key|230390|text|在我的例子中，我有一台独立的服务器，我将配置管理器中的sql+server端口默认端口1433更改为某个数字，并重新启动sql+service服务以使其生效，如果我登录到服务器，则可以通过management+studio连接到sql+server。但是我无法从我的本地计算机通过sql+server连接，我收到以下错误：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|230391|建立与SQL+Server的连接时发生网络相关错误或特定于实例的错误。服务器找不到或无法访问。验证实例名称是否正确，并|230392|该SQL+Server已配置为允许远程连接。(提供程序:命名管道提供程序，错误:+40+-无法打开到SQL+Server的连接)+(Microsoft+SQL+Server，错误:+5)|230393|我检查并验证了以下所有内容|230394|启用了-Named管道/TCP。允许-Remote连接。-Windows防火墙关闭-Created是一个例外(在我的情况下这是不必要的，因为服务器在相同的子网网络中)。在SQL+Server配置管理器中-Enabled所有内容。|230395|然后，我将端口号改回默认值1433，并重新启动sql+server服务，问题得到解决，我能够从本地管理工作室连接sql+server。|230396|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|P|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|Q|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|R|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|S|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|M|$]]

in my case, i had a standalone server, i changed the sql server port default port 1433 in configuration manager to some number and restarted the sql serve service to take effect,i was able to connect to the sql server through management studio if i login to the server. but i was not able to connect from my local machine through sql server, i was getting the error:

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and 

that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 5)

I checked and verified all the below

-Named pipes/TCP is enabled.
-Remote connections are allowed.
-Windows Firewall is off
-Created an exception for portin Windows Firewall( this was not necessary in my case as the server is in same subnet network).
-Enabled everything in SQL Server Configuration Manager.

then i chnaged back the port number to default 1433 and restarted the sql server service, and the issue got resolved and i am able to connect the sql server from my local management studio.

blocks|key|2895754|text|我也有同样的问题。我使用MSSQL+Server+Management+Studio+2017，并通过以下步骤解决了这个问题：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2895755|SQL+|2895756|检查SQL+Server服务服务是否正常工作。|unordered-list-item|2895757|
|2895758|还将检查工作状态是否良好SQL+Server+SQL+(MSSQLSERVER).|2895759|2895760|Also检查是否工作正常|2895761|2895762|并把它修好了。|2895763|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|V|8|@]|9|@]|A|$]]|$1|I|3|J|5|F|7|W|8|@]|9|@]|A|$]]|$1|K|3|H|5|6|7|X|8|@]|9|@]|A|$]]|$1|L|3|M|5|F|7|Y|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|R|$]]

I had the same problem. I use the MSSQL Server Management Studio 2017 and solved this problem using these steps:

<ol>
<li>Check for working fine SQL Server Services services or not.</li>
<li>Also check for working in good condition SQL Server (MSSQLSERVER).</li>
<li>Also check for working fine SQL Server Browser.</li>
<li>Restart SQL Server (MSSQLSERVER)</li>
</ol>

and fixed it.

blocks|key|233752|text|你会发现你的数据库名很可能是不正确的，你会在VS中看到服务器名，比如"DESKTOP-0I14BKI“，但如果你打开SSMS，你会看到DESKTOP-0I14BKI\SQLBLAHBLAH，只需在VS连接属性中将"\SQLBLAHBLAH”添加到你的“服务器名”中。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|233753|您将看到：|offset|length|style|BOLD|233754|📷|atomic|233755|​|233756|要修复的：|233757|233758|233759|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/a1eb77864cab06ba6df500e757626e88.png|imageAlt|1|https://ask.qcloudimg.com/http-save/yehe-900000/cc1df5cf23577b3dddf6f20f42a54740.png^0|0|0|4|0|0|1|0|0|0|4|1|0|0|1|1|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|12|8|@$D|13|E|14|F|G]]|9|@]|A|$]]|$1|H|3|I|5|J|7|15|8|@]|9|@$D|16|E|17|1|18]]|A|$]]|$1|K|3|L|5|6|7|19|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|1A|8|@$D|1B|E|1C|F|G]]|9|@]|A|$]]|$1|O|3|I|5|J|7|1D|8|@]|9|@$D|1E|E|1F|1|1G]]|A|$]]|$1|P|3|L|5|6|7|1H|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|1I|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X|Y|-4]]|Z|$5|T|U|V|A|$W|10|Y|-4]]]]

You will find most likely your DB name is not correct, you will see the server name in VS like "DESKTOP-0I14BKI" but if you open up SSMS you will see DESKTOP-0I14BKI\SQLBLAHBLAH , simply add "\SQLBLAHBLAH" (instance name) to your "server name" in VS connection properties.

You will see:
<a href="https://i.stack.imgur.com/LWAmG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/LWAmG.png" alt="enter image description here"></a>

To Fix:
<a href="https://i.stack.imgur.com/GwR2y.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GwR2y.png" alt="enter image description here"></a>

blocks|key|230356|text|请尝试以下步骤：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|230357|SQL+|230358|打开服务窗口(打开“运行框”，键入services.msc).|unordered-list-item|230359|
|230360|Looking表示服务(带有SQL前缀)。|230361|启动它们(如果无法启动。转到步骤4).|ordered-list-item|230362|Right_click到每个服务->属性->更改到选项卡“登录”->选择登录为“本地...”->+0K。然后再次启动SQL服务。|230363|230364|230365|尝试使用Open+SQL并连接数据库。|230366|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|W|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|X|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|F|7|Z|8|@]|9|@]|A|$]]|$1|K|3|L|5|M|7|10|8|@]|9|@]|A|$]]|$1|N|3|O|5|M|7|11|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|12|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|13|8|@]|9|@]|A|$]]|$1|R|3|S|5|6|7|14|8|@]|9|@]|A|$]]|$1|T|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|U|$]]

Try the following steps:

<ol>
<li>Open Services window (open "run box" and type services.msc).</li>
<li>Looking for SQL services (with SQL prefix).</li>
<li>Start them (if cannot start. Goto step 4).</li>
<li>Right_click to each service -> Properties -> Change to tab "Log on"-> choise log on as "Local ..." -> 0K. Then start SQL services again.</li>
</ol>

Try Open SQL and connect database.

blocks|key|2895580|text|在我的示例中，我打开SQL+Server+Management+Studio并在数据库引擎中搜索SQLEXPRESS。它有两个实例，我选择了正确的一个。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2895581|​|2895582|📷|atomic|offset|length|2895583|2895584|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/c081686257afb0057b7158c73191bab7.png|imageAlt^0|0|0|0|1|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@$G|V|H|W|1|X]]|A|$]]|$1|I|3|C|5|6|7|Y|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|K|$L|$5|M|N|O|A|$P|Q|R|-4]]]]

In my case,
I opened SQL Server Management Studio and searched for SQLEXPRESS in my Database engine. 
It had two instances and I selected the correct one.

<a href="https://i.stack.imgur.com/Rm1Nl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Rm1Nl.png" alt="enter image description here"></a>

blocks|key|3109806|text|如果您正在使用Asp.net核心并使用appsettings.json，则将服务器写为本地主机，然后为已启用的命名管道编写sql+name，如下所示|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3109807|++"ConnectionString":+{
++++"dewDB":+"server=localhost\\dewelopersql;database=dewdb;User+ID=sa;password=XXXXX",
++},|code-block|syntax|javascript|3109808|entityMap^0|17|4|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

If you are working with Asp.net core and using appsettings.json than write server as localhost and after write sql instance name for enabled named pipe like this

<pre><code> "ConnectionString": {
 "dewDB": "server=localhost\\dewelopersql;database=dewdb;User ID=sa;password=XXXXX",
 },
</code></pre>

blocks|key|235833|text|执行完前面提到的所有步骤后，如果here仍然没有连接，请尝试在etc文件夹中的主机文件中添加IP地址的DNS。在连接字符串中添加IP地址而不是DNS名称应该是检查连接是否正常工作的临时解决方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|235834|entityMap|0|LINK|mutability|MUTABLE|url|http://social.msdn.microsoft.com/Forums/sqlserver/en-US/2a8f2e64-74cf-46f2-b2be-bbb08b1502cb/re-named-pipes-provider-error-40-could-not-open-a-connection-to-sql-server?forum=sqlreportingservices^0|G|4|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

After following all the steps mentioned <a href="http://social.msdn.microsoft.com/Forums/sqlserver/en-US/2a8f2e64-74cf-46f2-b2be-bbb08b1502cb/re-named-pipes-provider-error-40-could-not-open-a-connection-to-sql-server?forum=sqlreportingservices" rel="nofollow">here</a>, if it still does not connect, try adding the DNS with the IP address in the hosts file in the etc folder. Adding an IP address instead of DNS name in the connection string should be a temporary solution to check if the connection actually works.

blocks|key|3108742|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3108743|我尝试使用本地IP地址和公共IP地址进行连接。我试过了：|blockquote|3108744|3108745|可以，站点可以与启用了命名管道/TCP的服务器进行通信。允许远程连接。Windows防火墙关闭为Windows防火墙中的端口1433创建了一个例外。已在SQL+Server配置管理器中启用所有功能。|3108746|3108747|我保证并做了上面的事情，我只想分享一下双反斜杠|3108748|oBuilder.DataSource+=+"SPECIFICPCNAME\SQLEXPRESS"；|3108749|使用单个反斜杠会导致生成错误，即:+error+1无法识别转义序列|3108750|我希望这对下一个家伙有帮助--我牺牲了晚餐，夜宵和NBA的精彩时刻来解决这个问题(羞耻)|3108751|感谢Tamizh+venthan+%5E_%5E|3108752|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|-4|4|5|6|T|7|@]|8|@]|9|$]]|$1|A|3|B|4|C|6|U|7|@]|8|@]|9|$]]|$1|D|3|-4|4|5|6|V|7|@]|8|@]|9|$]]|$1|E|3|F|4|5|6|W|7|@]|8|@]|9|$]]|$1|G|3|-4|4|5|6|X|7|@]|8|@]|9|$]]|$1|H|3|I|4|5|6|Y|7|@]|8|@]|9|$]]|$1|J|3|K|4|5|6|Z|7|@]|8|@]|9|$]]|$1|L|3|M|4|5|6|10|7|@]|8|@]|9|$]]|$1|N|3|O|4|5|6|11|7|@]|8|@]|9|$]]|$1|P|3|Q|4|5|6|12|7|@]|8|@]|9|$]]|$1|R|3|-4|4|5|6|13|7|@]|8|@]|9|$]]]|S|$]]

<blockquote>
 I tried using the local IP address to connect as well as a public one.
 I've tried:
 
 Yes, the site can communicate with the server Named pipes/TCP is
 enabled. Remote connections are allowed. Windows Firewall is off
 Created an exception for port 1433 in Windows Firewall. Enabled
 everything in SQL Server Configuration Manager.
</blockquote>

i ensured and did the above as well and I just want to share that the DOUBLE BACKSLASH 

oBuilder.DataSource = "SPECIFICPCNAME\SQLEXPRESS";

Using a SINGLE BACKSLASH resulted into a build error i.e.: Error 1 Unrecognized escape sequence 

I hope this helps the next guy - I've sacrificed dinner, midnight snack and NBA highlights time solving this (shame)

Thanks to [Tamizh venthan]
^_^

blocks|key|230449|text|通过转到计算机管理->SQL和服务来启用TCP/Ip和管道协议，确保服务已打开。启用防火墙上的端口。尝试以管理员身份通过命令提示符->登录；最后，用户名应为(本地)\SQLEXPRESS。希望这能有所帮助。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|230450|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Enable TCP/Ip , Piped Protocol by going to Computer Management ->SQL and Services, ensure the Service is On. Enbale the port on the Firewall. Try to login through Command Prompt -> as Admin; last the User Name
should be (local)\SQLEXPRESS. Hope this helps.

blocks|key|3108934|text|打开SQL+Server配置管理器|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3108935|3108936|从右侧选择SQL+Server服务。|ordered-list-item|3108937|从右侧找到您的服务器，然后转到其属性(右键单击)|3108938|将登录方法更改为本地系统。|3108939|3108940|​|3108941|📷|atomic|offset|length|3108942|3108943|3108944|3108945|3108946|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/75990a81dfb3065011f421e89c945f19.png|imageAlt|1|https://ask.qcloudimg.com/http-save/yehe-900000/82afd3d5cae32dfbec4a20a60c03a6e3.png^0|0|0|0|0|0|0|0|0|1|0|0|0|0|0|1|1|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|17|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|18|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|19|8|@]|9|@]|A|$]]|$1|H|3|I|5|E|7|1A|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|1C|8|@]|9|@]|A|$]]|$1|M|3|N|5|O|7|1D|8|@]|9|@$P|1E|Q|1F|1|1G]]|A|$]]|$1|R|3|L|5|6|7|1H|8|@]|9|@]|A|$]]|$1|S|3|L|5|6|7|1I|8|@]|9|@]|A|$]]|$1|T|3|N|5|O|7|1J|8|@]|9|@$P|1K|Q|1L|1|1M]]|A|$]]|$1|U|3|L|5|6|7|1N|8|@]|9|@]|A|$]]|$1|V|3|-4|5|6|7|1O|8|@]|9|@]|A|$]]]|W|$X|$5|Y|Z|10|A|$11|12|13|-4]]|14|$5|Y|Z|10|A|$11|15|13|-4]]]]

Open SQL Server Configuration Manager

<ol>
<li>Select SQL Server Services from right.</li>
<li>Find your server from right and go to its properties (with right click)</li>
<li>Change log on method to Local System.</li>
</ol>

<img src="https://i.stack.imgur.com/CfTZY.png" alt="enter image description here">

<img src="https://i.stack.imgur.com/BH4LK.png" alt="enter image description here">

blocks|key|3109264|text|我遇到了同样的问题，并通过禁用我的防火墙(ESET)解决了这个问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3109265|解决此问题的第一步应该是尝试从另一台计算机pinging您自己的计算机。如果您打开了防火墙，您可能无法ping通自己。我试着ping我自己的电脑，但是ping失败了(没有从服务器得到响应)|3109266|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I had the same problem and solved the problem by disabling my firewall(ESET).

The first step to solve this problem should be to try pinging your own computer from another computer. If you have firewall on, you may not be able to ping yourself. I tried pinging my own pc, then ping was failed(didnt get response from the server)

blocks|key|3109411|text|我正尝试在VS2015中添加一个新连接。这里的建议都不起作用。我怀疑向导中存在某种bug，特别是因为SSMS能够很好地连接，所以我决定试着欺骗它。啊，真灵!|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3109412|3109413|不是添加连接，而是使用“创建新的SQL+Server数据库”。输入您的服务器名称和新数据库的随机名称，例如测试成功，在VS中打开服务器资源管理器，找到数据连接中的连接，右键单击它并选择Modify+Connection.|ordered-list-item|3109414|Change“"test".|3109415|Assuming”(从步骤1开始)为您要连接的现有数据库的名称。单击[测试连接]。|3109416|删除您在步骤1中创建的临时数据库。|3109417|3109418|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|P|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|Q|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|R|8|@]|9|@]|A|$]]|$1|H|3|I|5|E|7|S|8|@]|9|@]|A|$]]|$1|J|3|K|5|E|7|T|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

I was trying to add a new connection in VS2015. None of the suggestions here worked. Suspecting some sort of a bug in the wizard, especially since SSMS was able to connect just fine, I decided to try and trick it. It worked!

<ol>
<li>Instead of adding the connection, use "Create new SQL Server Database". Enter your server name and a random name for the new DB, e.g. "test".</li>
<li>Assuming this succeeds, open Server Explorer in VS, locate the connection in Data Connections, right-click it and select Modify Connection.</li>
<li>Change "test" (from step 1) to the name of the existing database you want to connect to. Click "Test Connection". This time it should work!</li>
<li>Delete the temporary database you created in step 1.</li>
</ol>

blocks|key|233628|text|我想我还有一个解决方案。我最近更改了我的计算机名称，所以，在尝试了上述所有方法后仍然无法连接。我更改了服务器名称..服务器名称=>+(浏览了解更多信息)+=>在数据库引擎下，找到与计算机新名称相同的新服务器。这起作用了，生活又好起来了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|233629|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I have one more solution, I think.
I recently had changed my computer name so, after I couldn't connect still after trying all above methods.
I changed the Server name..
Server name => (browse for more) => under database engine, a new server was found same as computers new name.
This worked, and life is good again.

blocks|key|233631|text|我在这个问题上挣扎了很长时间才意识到我的错误-我在连接字符串中使用逗号而不是分号|type|unstyled|depth|inlineStyleRanges|entityRanges|data|233632|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I struggled for ages on this one before I realized my error - I had used commas instead of semicolons in the connect string

blocks|key|236163|text|我有这个问题，但上面的建议都没有解决它。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|236164|当我将我的网站部署到IIS时，我看到了这个问题。修复方法是针对默认应用程序池进入高级设置，并将identity属性从默认更改为Administrator。|236165|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I had this issue but none of the suggestions above fixed it. 

I was seeing this issue when I deployed my website to IIS. The fix was to go into advanced settings against the default app pool and change the identity property from the default to Administrator.

blocks|key|233708|text|对我来说，这是一个防火墙问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|233709|首先，您必须添加端口(例如1444，也可能是1434)，但是|233710|C:\Program+Files+(x86)\Microsoft+SQL+Server\90\Shared\sqlbrowser.exe|code-block|syntax|javascript|233711|和|233712|%25ProgramFiles%25\Microsoft+SQL+Server\MSSQL12.SQLEXPRESS\MSSQL\Binn\SQLAGENT.EXE|233713|我第二次遇到这个问题是在我回到防火墙时，路径不正确，我需要将表单12更新为13！只需单击程序和服务选项卡中的浏览，即可实现这一点。|233714|最后，尝试运行该命令|233715|233716|+EXEC+xp_readerrorlog+0,1，“无法注册服务主体名称”，空|blockquote|233717|233718|233719|对于我来说，它返回了错误原因|233720|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|13|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|14|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|15|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|16|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|17|8|@]|9|@]|A|$]]|$1|R|3|S|5|T|7|18|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|19|8|@]|9|@]|A|$]]|$1|V|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]|$1|W|3|X|5|6|7|1B|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1C|8|@]|9|@]|A|$]]]|Z|$]]

For me it was a Firewall issue.

First you have to add the port (such as 1444 and maybe 1434) but also 

<pre><code>C:\Program Files (x86)\Microsoft SQL Server\90\Shared\sqlbrowser.exe
</code></pre>

and 

<pre><code>%ProgramFiles%\Microsoft SQL Server\MSSQL12.SQLEXPRESS\MSSQL\Binn\SQLAGENT.EXE
</code></pre>

The second time I got this issue is when I came back to the firewall, the paths were not correct and I needed to update form 12 to 13! Simply clicking on browse in the Programs and Services tab helped to realise this.

Finally, try running the command

<blockquote>
 EXEC xp_readerrorlog 0,1,"could not register the Service Principal Name",Null
</blockquote>

For me, it returned the error reason

blocks|key|2895830|text|我在这个页面上尝试了几乎所有的东西，但我有一些潜在的问题，这些问题实际上是需要解决的。我无法执行某些操作，例如打开SQL+Server配置管理器，最终导致WMI提供程序文件损坏/丢失。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2895831|根据我所读到的，有很多乏味的方法来解决这个问题，但tweaking.com的工具能够删除和替换/修复我的WMI+(Windows+Management+Instrumentation)提供程序文件。|2895832|我曾经做过电脑维修，总的来说，tweaking.com工具真的给我留下了深刻的印象，它是我去过的一个WMI论坛页面上的建议。|2895833|修复此问题后，我能够本地和远程连接到我的SQL数据库。|2895834|希望这对某些人有帮助。|2895835|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|M|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|N|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|O|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|P|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|K|$]]

I tried pretty much everything on this page but I had some underlying issues which were actually what needed to be resolved. I was unable to do certain things like open SQL Server Configuration Manager, which ended up being corrupt/missing WMI provider files.

There are lots of tedious ways to resolve this issues according to what I've read, but the tool from tweaking.com was able to remove and replace/repair my WMI (Windows Management Instrumentation) Provider files.

I used to do computer repair and overall the tweaking.com tool really impressed me, and it was suggested from one of the WMI error forum pages I went to.

After I fixed this issue I was able to connect to my SQL db, both locally and remotely.

Hope this helps someone.

blocks|key|2895853|text|打开服务器上的端口号1433以进行sql+remote连接|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2895854|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

open port number 1433 on your server for sql remote connection

blocks|key|233838|text|如果您尝试重新启动MSSQLSERVER服务，但它不起作用，这可能是一种解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|233839|如果您使用的是SQLExpress，则您的服务器名称应为以下ComputerName。然而，对于SQLDeveloper，您不必在ComputerName之后正确使用SQLDeveloper。|233840|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

If you tried restarting the MSSQLSERVER service, and it did not work, this might be a solution: 

If you are using SQLExpress, your server name should be as the following ComputerName\SQLExpress. However, for SQLDeveloper, you do not have to right SQLDeveloper after your ComputerName.

blocks|key|3109374|text|我已经建议了以下步骤来解决您的问题:如何修复错误‘命名管道提供程序，错误40+-无法打开到’SQL+‘的连接’|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3109375|SQL+|3109376|+check+for+working+fine+SQL+Server+services+on+not。|unordered-list-item|offset|length|style|BOLD|3109377|
|3109378|还会检查SQL+Server+(MSSQLSERVER).|3109379|3109380|Also+check+for+working+for+working+for+good+SQL+Server+Browser.|3109381|3109382|Delete所有早期的别名，现在根据您的SQL+Server默认端口端口创建新的别名单击实例中的客户端协议，然后单击TCP/IP，现在单击鼠标右键，打开属性，在这里您可以确保您的默认端口正常工作，然后单击右键，单击"Property“选项，然后单击”+Connections+“选项卡，最后勾选”Allow+remote+Connections+to+this+server.|CODE|3109383|3109384|Check++right+working+or+your+Ping+IP+Host.|3109385|
“。|3109386|entityMap^0|0|0|O|J|0|0|0|0|18|I|0|0|B|2|Y|4A|1S|3G|0|0|0|16|0|16|0|1|2|1|2|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|14|8|@$G|15|H|16|I|J]]|9|@]|A|$]]|$1|K|3|L|5|6|7|17|8|@]|9|@]|A|$]]|$1|M|3|N|5|F|7|18|8|@]|9|@]|A|$]]|$1|O|3|L|5|6|7|19|8|@]|9|@]|A|$]]|$1|P|3|Q|5|F|7|1A|8|@$G|1B|H|1C|I|J]]|9|@]|A|$]]|$1|R|3|L|5|6|7|1D|8|@]|9|@]|A|$]]|$1|S|3|T|5|F|7|1E|8|@$G|1F|H|1G|I|J]|$G|1H|H|1I|I|J]|$G|1J|H|1K|I|U]]|9|@]|A|$]]|$1|V|3|L|5|6|7|1L|8|@]|9|@]|A|$]]|$1|W|3|X|5|F|7|1M|8|@$G|1N|H|1O|I|J]|$G|1P|H|1Q|I|U]]|9|@]|A|$]]|$1|Y|3|Z|5|6|7|1R|8|@$G|1S|H|1T|I|J]|$G|1U|H|1V|I|U]]|9|@]|A|$]]|$1|10|3|-4|5|6|7|1W|8|@]|9|@]|A|$]]]|11|$]]

I have suggested below steps to resolve your issue How do I fix the error 'Named Pipes Provider, error 40 - Could not open a connection to' SQL Server'

<ol>
<li>Check for working fine SQL Server Services services or not.</li>
<li>Also check for working in good condition SQL Server (MSSQLSERVER).</li>
<li>Also check for working fine SQL Server Browser.</li>
<li>Delete all earlier Aliases, now create new aliases as per your requirements.</li>
<li>Now check for working of SQL Server Default Port 1433</li>
<li>Next click on Client Protocols in instance, then click on TCP/IP, now click on mouse right click, open the Property, here you can make assure your working fine your default port SQL 1433.</li>
<li>Open your SQL Server Management Studio, then right click, click on "Property" option and then click on Connections tab, then finally tick for Allow remote Connections to this server.</li>
<li>Check for right working or your Ping IP Host.</li>
</ol>

I can't seem to connect to my database from a site. I get this error:

<blockquote>
 Named Pipes Provider, error: 40 - Could not open a connection to SQL Server
</blockquote>

I tried using the local IP address to connect as well as a public one. I've tried:

<ol>
<li>Yes, the site can communicate with the server</li>
<li>Named pipes/TCP is enabled.</li>
<li>Remote connections are allowed.</li>
<li><a href="http://en.wikipedia.org/wiki/Windows_Firewall" rel="noreferrer">Windows Firewall</a> is off</li>
<li>Created an exception for port 1433 in Windows Firewall.</li>
<li>Enabled everything in SQL Server Configuration Manager.</li>
</ol>

What else can I do here?

How do I fix the error 'Named Pipes Provider, error 40 - Could not open a connection to' SQL Server'?

SQL数据库

SQL Server

数据库

服务器

虚拟机

防火墙

Windows

我似乎无法从网站连接到我的数据库。我得到了这个错误：命名管道提供程序，错误: 40 -无法打开到SQL Server的连接我尝试使用本地IP地址和公共IP地址进行连接。我试过了：是，站点可以与服务器通信命名管道/TCP is enabled.Remote connections is allowed. is off中的端口1433在配置管理器中创建了一个例外。我还能在这里做些什么？

问如何修复错误‘命名管道提供程序，错误40 -无法打开到’SQL Server‘的连接？
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回答 31

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问如何修复错误‘命名管道提供程序，错误40 -无法打开到’SQL Server‘的连接？EN

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问如何修复错误‘命名管道提供程序，错误40 -无法打开到’SQL Server‘的连接？
EN