Symptoms
- Mail forwarding fails, error in
/var/log/maillogplesk postfix/smtp[8055]: AABBCCDD11: to=<sender@example.com>, relay=<relay_host_hostname>[203.0.113.2]:587, delay=0.16, delays=0.02/0.02/0.08/0.03, dsn=5.0.0, status=bounced (host <relay_host_hostname>[203.0.113.2] said: 550-Verification failed for <SRS0=p0uz=4E=example.com=sender@example2.com> 550-Previous (cached) callout verification failure 550 Invalid sender <SRS0=p0uz=4E=example.com=sender@example2.com> (in reply to MAIL FROM command)
Cause
Sender Rewriting Scheme (SRS) support is enabled in Plesk, however it is not supported on the relay host.
Resolution
Recommended solution is to enable acceptance of SRS for emails from Plesk on the relay host.
Disabling SRS support in Plesk (not recommended).
Warning: This solution will make the environment less secure because the sender's email policy will be ignored.
In case it is not possible to enable SRS on the relay host, SRS can be disabled in Plesk following the next steps:
-
Connect to the server via SSH
- Open the
/etc/postfix/master.cf
plesk_virtual unix - n n - - pipe flags=DORhu user=popuser:popuser argv=/usr/lib64/plesk-9.0/postfix-local -f ${sender} -d ${recipient} -p /var/qmail/mailnames
- Add
-s
plesk_virtual unix - n n - - pipe flags=DORhu user=popuser:popuser argv=/usr/lib64/plesk-9.0/postfix-local -f ${sender} -d ${recipient} -p /var/qmail/mailnames -s
- Restart the
postfix# systemctl restart postfix