title: VestaCP/exim mail server returns 550 smtp auth requried
body: <p>I have just installed VestaCP on a fresh CentOS VPS.</p>
  
  <p>I have set up email for one domain. All mail sent to that domain bounces with the error 550 smtp auth requried</p>
  
  <p>I have commented out the following;</p>
  
  <pre><code>deny    message       = smtp auth requried
  </code></pre>
  
  <p>from exim.conf</p>
  
  <p>I have turned off anti-spam.</p>
  
  <p>I still get the bounce with this message.</p>
  
  <p>Specifically, if I send an email from a gmail account google responds:</p>
  
  <pre><code>Technical details of permanent failure: 
  Google tried to deliver your message, but it was rejected by the server for the recipient domain foobar.tld by mail.foobar.tld. [x.x.x.x].
  
  The error that the other server returned was:
  550 smtp auth requried
  </code></pre>
  
  <p>Any experience with this? I have seen the problem on a number of threads but have not found a solution.</p>