title: Zend Mail - Email is not sent
body: <p>I have a problem sending a registration email via zend_mail. The mail is transmitted only to mails that have a @gmail.com.</p>
  
  <pre><code>$email = "test@gmx.net";
  $mail = new Zend_Mail ();
  $mail-&gt;setBodyText ( 'some text' );
  $mail-&gt;setBodyHtml ( 'some text' );
  $mail-&gt;setFrom ( 'support@mysite.net', 'MySite.net' );
  $mail-&gt;addTo ( $email, $email );
  $mail-&gt;setSubject ( 'test' );
  $mail-&gt;send ();
  </code></pre>
  
  <p>If the user has another email provider the email is not sent.</p>
  
  <p>Any ideas?</p>