title: Error 550-5.2.1 The user you are trying to contact is receiving mail at a rate that
body: <p>I am facing a very annoying issue on my server.
  My Linux Server has a system to send out notifications to my gmail everyday.</p>
  
  <p>But my server returns errors below.</p>
  
  <blockquote>
    <p>relay=aspmx.l.google.com[74.125.70.26]:25, delay=0.1,
    delays=0.03/0/0.05/0.02, dsn=5.2.1, status=bounced (host
    aspmx.l.google.com[74.125.70.26] said: 550-5.2.1 The user you are
    trying to contact is receiving mail at a rate that 550-5.2.1 prevents
    additional messages from being delivered. For more 550-5.2.1
    information, please visit 550 5.2.1
    <a href="http://support.google.com/mail/bin/answer.py?answer=6592" rel="nofollow">http://support.google.com/mail/bin/answer.py?answer=6592</a>
    r9si29669915icw.94 - gsmtp (in reply to RCPT TO command))</p>
  </blockquote>
  
  <p>I know that Google wants to avoid to receive too many emails from the same machine within a period. It should work after a few time.</p>
  
  <p>But even my server has not sent out any emails for 24 hours, the first email after the period is still bounced (the error is still returned).</p>
  
  <p>Do you have any ideas?</p>