Issue Postfix - warning: connect to transport private/plesk-domain.org.uk-123.145.167.189-: Connection refused

[MHC_1]

Server operating system version

Alma Linux 9

Plesk version and microupdate number

Obsidian 18.0.6

We have the following mail log details:

/var/log/mail.log

Jun 9 10:02:05 serverName postfix/smtpd[2253641]: connect from host86-178-175-114.range86-178.btcentralplus.com[86.178.175.114]

Jun 9 10:02:06 serverName postfix/smtpd[2253641]: 22BBB52000093: client=host86-178-175-114.range86-178.btcentralplus.com[86.178.175.114], sasl_method=CRAM-MD5, sasl_username=[email protected]

Jun 9 10:02:06 serverName psa-pc-remote[2253076]: 22BBB52000093: from=<[email protected]> to=<[email protected]>

Jun 9 10:02:06 serverName postfix/cleanup[2253834]: 22BBB52000093: message-id=<[email protected]>

Jun 9 10:02:08 serverName amavis[2245222]: (2245222-07) Passed CLEAN {AcceptedOutbound}, AM.PDP-SOCK/SUBMISSION LOCAL [86.178.175.114] [86.178.175.114] <[email protected]> -> <[email protected]>, Queue-ID: 22BBB52000093, Message-ID: <[email protected]>, mail_id: oWVRfxJQCDlT, Hits: -0.875, size: 4604, 2075 ms

Jun 9 10:02:08 serverName psa-pc-remote[2253076]: 22BBB52000093: py-limit-out: stderr: INFO:__main__:Setting 'X-PPP-Vhost' header to 'domain.org.uk'

Jun 9 10:02:08 serverName psa-pc-remote[2253076]: 22BBB52000093: py-limit-out: stderr: PASS

Jun 9 10:02:08 serverName psa-pc-remote[2253076]: 22BBB52000093: spf: stderr: PASS

Jun 9 10:02:08 serverName psa-pc-remote[2253076]: 22BBB52000093: check-quota: stderr: SKIP

Jun 9 10:02:08 serverName psa-pc-remote[2253076]: 22BBB52000093: dk_sign: stderr: PASS

Jun 9 10:02:08 serverName postfix/qmgr[2252799]: 22BBB52000093: from=<[email protected]>, size=4577, nrcpt=1 (queue active)

Jun 9 10:02:08 serverName postfix/qmgr[2252799]: warning: connect to transport private/plesk-domain.org.uk-123.145.167.189-: Connection refused

Jun 9 10:02:08 serverName postfix/error[2267273]: 22BBB52000093: to=<[email protected]>, relay=none, delay=2.4, delays=2.4/0/0/0, dsn=4.3.0, status=deferred (mail transport unavailable)

Jun 9 10:02:09 serverName dovecot[2253344]: service=imap, user=[email protected], ip=[86.178.175.114]. Disconnected: Logged out rcvd=4737, sent=119008

Jun 9 10:02:09 serverName dovecot[2253344]: imap-login: Login: user=<[email protected]>, method=CRAM-MD5, rip=86.178.175.114, lip=123.145.167.189, mpid=2269172, TLS, session=<I3VHrCA3qcpWsq9y>

Note: 123.145.167.189 is the server IP.
The core detail here is:

Jun 9 10:02:08 serverName postfix/qmgr[2252799]: warning: connect to transport private/plesk-domain.org.uk-123.145.167.189-: Connection refused

BUT:
Other domains on the server are sending and receiving OK. This domain (multiple addresses on this domain) has an issue.

Due to this I am wary of doing the Plesk Repair on the main.cf or Master.cf files.

How can we find out what the specific issue is?

Everything was working fine until a couple days ago. The email address now has 30 mails queued all with the above issue.

 

[Kaspar]

Perhaps this support article helps to narrow down the issue:

https://support.plesk.com/hc/en-us/articles/12377953797783-Unable-to-send-email-in-Plesk-mail-transport-unavailable

 

[MHC_1]

Perhaps this support article helps to narrow down the issue:

https://support.plesk.com/hc/en-us/articles/12377953797783-Unable-to-send-email-in-Plesk-mail-transport-unavailable

Yes I have already read and used this documentation. All parts of the settings are as set in the documentation.

As stated - it seems to be only one domain that is at issue.

How do we debug and resolve where the issue is coming from?

 

[Sebahat.hadzhi]

Can you recall of making any recent changes on master.cf, main.cf, or any mail settings/configuration whatsoever?

 

[MHC_1]

Can you recall of making any recent changes on master.cf, main.cf, or any mail settings/configuration whatsoever?

Master.cf has not been changed.

main.cf has been changed as per "smtpd_client_restrictions" from https://serverfault.com/questions/1...f-reject-rbl-client-in-smtpd-client-restricti . No other changes.

There is a paid for Warden Anti-spam which integrates with both main.cf and master.cf I think . "Warden Anti-spam and Virus Protection" . Nothing else I'm aware of interacts with Postfix like this.

 

[Sebahat.hadzhi]

Thanks for the confirmation. Was that change performed before or after the occurrence of the issue? As far as I am aware, that particular issue could result from such changes.

 

[MHC_1]

Thanks for the confirmation. Was that change performed before or after the occurrence of the issue? As far as I am aware, that particular issue could result from such changes.

The change occurred several days before and all was running smoothly with multiple postfix restarts.

 

[Sebahat.hadzhi]

For the sake of testing, could you please set the value to back to the default one. That should be:

smtpd_client_restrictions = permit_mynetworks, permit_sasl_authenticated

 

[MHC_1]

For the sake of testing, could you please set the value to back to the default one. That should be:

We did in the end run the "Plesk mail repair" command in the terminal; this does seem to have caught this issue, although now other clients are claiming emails they send are not being delivered so that's something else we're needing to look into.

Anyways,

smtpd_client_restrictions = reject_unknown_client_hostname, permit_mynetworks, permit_sasl_authenticated

Is now the current code in main.cf .