问PHP中的名称服务器与正则表达式匹配时出现问题

EN

WhoIs Result: 
Domain name: example-domain.co.uk 
Data validation: Nominet was not able to match the registrant's name and/or address against a 3rd party source on 23-Mar-2017 
Registrar: eNom LLC [Tag = ENOM] 
URL: http://www.enom.com 
Relevant dates: 
Registered on: 23-Mar-2017 
Expiry date: 23-Mar-2019 
Last updated: 26-Mar-2018 
Registration status: Registered until expiry date. 
Name servers: dns1.registrar-servers.com dns2.registrar-servers.com 

WHOIS lookup made at 12:26:52 31-May-2018 -- This WHOIS information is provided for free by Nominet UK the central registry for .uk domain names. This information and the .uk WHOIS are: Copyright Nominet UK 1996 - 2018. You may not access the .uk WHOIS or use any data from it except as permitted by the terms of use available in full at https://www.nominet.uk/whoisterms, which includes restrictions on: (A) use of the data for advertising, or its repackaging, recompilation, redistribution or reuse (B) obscuring, removing or hiding any or all of this notice and (C) exceeding query rate or volume limits. The data is provided on an 'as-is' basis and may lag behind the register. Access may be withdrawn or restricted at any time.

$re = '/(?:\G(?!\A)|Name Servers?:)\h*\K\S+/i';
if (preg_match_all($re, $whoisRes, $matches)) {
    $name_servers = $matches;
} 
if (preg_match('/Creation Date: ([0-9]+\-[0-9]+\-[0-9]+)/i', 
$whoisRes, $match)) {
    $domain_date = trim($match[1]);
    $creation_date = strtotime(trim($match[1]));
    $domainage = dateDiff("now", $creation_date) . "\n";
} elseif (preg_match('/Registered on: ([0-9]+\-[a-zA-Z]+\-[0-9]+)/i', 
$whoisRes, $match)) {
    $domain_date = trim($match[1]);
    $creation_date = strtotime(trim($match[1]));
    $domainage = dateDiff("now", $creation_date) . "\n";
} else {
    $domainage = 'No Registration Date Found';
}
echo "URL: $url [$online]<br><br>";
echo "Load Time: $response_text [$overall_text]<br><br>";
echo "Name Servers:"; var_dump($name_servers); echo"<br><br>";
echo "Title: $title<br><br>";
echo "Description: $description<br><br>";
echo "Keywords: $keywords<br><br>";
echo "WhoIs Result: $whoisRes<br><br>";
echo "Domain Age: $domainage [$domain_date]<br><br>";