Symptoms
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SendGrid is integrated with Postfix on a Plesk server.
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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 from=john_doe@example.com
postfix/cleanup[7767]: 8AB3920D44: message-id=b3294ebad8d93894df5f4ac4da7a67fd@domain.tld
postfix/qmgr[1480]: 8AB3920D44: from=john_doe@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
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=john_doe@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)
Cause
SendGrid is not properly configured.
Resolution
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Disable SendGrid in Postfix configuration defined in
/etc/postfix/main.cf. -
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.