title: PHP PEAR Mail: Relay access denied
body: <p>I can send emails to myself and other people on my mail server using PEAR Mail. But when I try to send to another server, I get an error:</p>
  
  <blockquote>
    <p>Relay access denied.</p>
  </blockquote>
  
  <p>I've checked the SMTP configs and they're exactly the same as in my email client.</p>
  
  <p>What could it be?</p>