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

Symptoms

• SendGrid is integrated with Postfix on a Plesk server.

• A sender receives the following delivery report after sending an email message:

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

• One of the following messages is logged in /var/log/maillog:

  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 [email protected]
  postfix/cleanup[7767]: 8AB3920D44: [email protected]
  postfix/qmgr[1480]: 8AB3920D44: [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: [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: [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)

Cause

SendGrid is not properly configured.

Resolution

1. Disable SendGrid in Postfix configuration defined in /etc/postfix/main.cf.

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 contactSendGrid Technical Support.