phpMailer不向外部域发送电子邮件

Question

我可以将电子邮件发送到主机域上的电子邮件地址，因此发送电子邮件到me@domain.com工作，邮件主机是domain.com，但如果我发送到me@gmail.com，它不会来了，我没有从phpMailer得到任何错误，启用调试，它显示一切都已完成。这是我的phpMailer设置：

require_once("class.phpmailer.php");                    

$mail = new PHPMailer();
$mail->IsSMTP(); // set mailer to use SMTP
$mail->SMTPDebug = 2;
$mail->Host = "mail.mydomain.co.uk"; // specify main and backup server                  
$mail->SMTPAuth = true; // turn on SMTP authentication                  
$mail->Username = "sendmail@mydomain.co.uk"; // SMTP username                   
$mail->Password = "password"; // SMTP password                  
$mail->From = "info@mydomain.com"; //do NOT fake header.                    
$mail->FromName = "Me";                 
$mail->AddAddress("you@gmail.com"); // Email on which you want to send mail                                         
$mail->Subject = "Just a Test";                 
$mail->Body = "Hello. I am testing <b>PHP Mailer.</b>";

if(!$mail->Send()){

    echo $mail->ErrorInfo;

}else{

    echo "<p>Thank you, we will be in touch shortly</p>";

}

发生了什么事？就邮件而言，它已发送，因为我回来了

SMTP -> FROM SERVER:250 Requested mail action okay, completed 
SMTP -> FROM SERVER:250 Requested mail action okay, completed 
SMTP -> FROM SERVER:354 Start mail input; end with . 
SMTP -> FROM SERVER:250 Requested mail action okay, completed