title: Domain of sender address does not exist (in reply to MAIL FROM command)
body: <p>I am trying to send a mail using <code>/usr/sbin/sendmail</code> and running into error Domain of sender address does not exist (in reply to MAIL FROM     command),I tried with different usernames but issue still persists,any pointers on how to fix it?</p>
  
  <pre><code>Date: Mon, 12 Feb 2018 22:28:32 -0800 (PST)
  From: MAILER-DAEMON@fullusernames-MacBook-Pro-2.local (Mail Delivery System)
  Subject: Undelivered Mail Returned to Sender
  To: username@fullusernames-MacBook-Pro-2.local
  Auto-Submitted: auto-replied
  MIME-Version: 1.0
  Content-Type: multipart/report; report-type=delivery-status;
          boundary="28C8A2004E5238.1518503312/fullusernames-MacBook-Pro-2.local"
  Content-Transfer-Encoding: 8bit
  Message-Id: &lt;20180213062832.A40612004E533E@fullusernames-MacBook-Pro-2.local&gt;
  
  This is a MIME-encapsulated message.
  
  --28C8A2004E5238.1518503312/fullusernames-MacBook-Pro-2.local
  Content-Description: Notification
  Content-Type: text/plain; charset=utf-8
  Content-Transfer-Encoding: 8bit
  
  This is the mail system at host fullusernames-macbook-pro-2.local.
  
  I'm sorry to have to inform you that your message could not
  be delivered to one or more recipients. It's attached below.
  
  For further assistance, please send mail to postmaster.
  
  If you do so, please include this problem report. You can
  delete your own text from the attached returned message.
  
                     The mail system
  
  &lt;username@company.com&gt;: host nwk-aaemail-lapp01.company.com[17.151.62.66] said: 553
      5.1.8 Domain of sender address does not exist (in reply to MAIL FROM
      command)
  
  --28C8A2004E5238.1518503312/fullusernames-MacBook-Pro-2.local
  Content-Description: Delivery report
  Content-Type: message/delivery-status
  
  Reporting-MTA: dns; fullusernames-MacBook-Pro-2.local
  X-Postfix-Queue-ID: 28C8A2004E5238
  X-Postfix-Sender: rfc822; username@fullusernames-MacBook-Pro-2.local
  Arrival-Date: Mon, 12 Feb 2018 22:22:09 -0800 (PST)
  
  Final-Recipient: rfc822; username@company.com
  Original-Recipient: rfc822;username@company.com
  Action: failed
  Status: 5.1.8
  Remote-MTA: dns; nwk-aaemail-lapp01.company.com
  Diagnostic-Code: smtp; 553 5.1.8 Domain of sender address does not exist
  
  --28C8A2004E5238.1518503312/fullusernames-MacBook-Pro-2.local
  Content-Description: Undelivered Message
  Content-Type: message/rfc822
  Content-Transfer-Encoding: 8bit
  </code></pre>