Emails from a Plesk server are not delivered when SendGrid is integrated with Postfix: cannot get sender domain

Symptoms

• SendGrid is integrated with Postfix in a Plesk server.

• Following error occurs in /var/log/maillog in an attempt to send message:

  check-quota[7763]: cannot get sender domain
  check-quota[7763]: Unable to intialize check-quota mail handler 
  plesk sendmail[7762]: Error during 'check-quota' handler 
  postfix/pickup[1479]: 8AB3920D44: uid=10000 from=[email protected]
  postfix/cleanup[7767]: 8AB3920D44: message-id=[email protected]
  postfix/qmgr[1480]: 8AB3920D44: from=[email protected], size=4843, nrcpt=1 (queue active)
  postfix/smtp[7753]: connect to mail.example.com.br[203.0.112.2]:25: Connection timed out 
  postfix/smtp[7753]: 8AB3920D44: to=[email protected], relay=none, delay=30, delays=0.01/0/30/0, dsn=4.4.1, status=deferred (connect to mail.example.com[203.0.112.2]:2

  ---

  postfix/smtpd[10873]: disconnect from localhost[::1]
  dovecot: service=imap, [email protected], ip=[::1]. Logged out rcvd=493, sent=652 
  postfix/smtp[10880]: 779F720D1F: to=[email protected], relay=smtp.sendgrid.net[203.0.112.2]:587, delay=0.33, delays=0.1/0.02/0.18/0.02, dsn=5.0.0, status=bounced (host smtp.sendgrid.net[203.0.112.2] said: 550 Unauthenticated senders not allowed (in reply to MAIL FROM command))

• User receives following delivery report in attempt to send a message:

  Action: failed
  Status: 5.0.0 
  Remote-MTA: dns; smtp.sendgrid.net 
  Diagnostic-Code: smtp; 550 Unauthenticated senders not allowed

Cause

SendGrid is misconfigured.

Resolution

Verify SendGrid is properly configured:

1. Disable SendGrid as a first step.

2. Then check that SendGrid is integrated with Postfix properly according to the SendGrid documentation .

   Note: For questions about configuring and troubleshooting configuration of Postfix and SendGrid contact SendGrid Technical Support .