Emails are not delivered when SendGrid is integrated with Postfix: cannot get sender domain

Symptoms

• SendGrid is integrated with Postfix.

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

  CONFIG_TEXT: 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=<johndoe@example.com>
  postfix/cleanup[7767]: 8AB3920D44: message-id=<b3294ebad8d93894df5f4ac4da7a67fd@domain.tld>
  postfix/qmgr[1480]: 8AB3920D44: from=<johndoe@example.com>, 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=<suport@example.com>, 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

  or

  CONFIG_TEXT: postfix/smtpd[10873]: disconnect from localhost[::1]
  dovecot: service=imap, user=johndoe@example.com, ip=[::1]. Logged out rcvd=493, sent=652
  postfix/smtp[10880]: 779F720D1F: to=<johndoe@domain.tld>, 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:
  

  CONFIG_TEXT: 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

1. Disable SendGrid.

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

For further assistance contact SendGrid Technical Support .