如何使用Exchange 和c#在我的域外发送电子邮件

using System;
using Microsoft.Exchange.WebServices.Data;

class Program
{
    static void Main(string[] args)
    {
        ExchangeService service = new ExchangeService(ExchangeVersion.Exchange2013_SP1);
        service.Credentials = new WebCredentials("username", "password");
        service.Url = new Uri("https://outlook.office365.com/EWS/Exchange.asmx");

        EmailMessage email = new EmailMessage(service);
        email.ToRecipients.Add("recipient@example.com");
        email.Subject = "Hello from C#";
        email.Body = "This email was sent from C# using Exchange and EWS.";
        email.Send();
    }
}