Resolved Mail to postmaster@hostname is no longer delivered.

[rik]

Hi,

Server -> System Settings -> Full hostname
a20.example.tld

Emails to [email protected] were being received correctly.

I accidentally added the a20.example.tld domain to Plesk.
Deleted a20.example.tld.
Mail addressed to [email protected] is no longer delivered.
What should I do to fix it?

Plesk Obsidian 18.0.32 Update #2
Web Admin Edition
OS: ‪CentOS Linux 7.9.2009

 

[Bitpalast]

This is a strange behavior, because the postmaster address will always be delivered to the system admin address. If you have the domain set-up or not, does not matter. Please check /var/log/maillog when sending something to the postmaster address what the mail server is doing with these mails.

 

[rik]

Thank you for your reply. It was as follows.

Email sent.
[email protected](hostname a16.example.tld) --> [email protected]

+------------------------------
/var/log/maillog

Jan 14 21:03:38 a20 postfix/smtpd[9753]: connect from a16.example.tld[xx.xxx.xxx.xxx]
Jan 14 21:03:38 a20 postfix/smtpd[9753]: NOQUEUE: reject: RCPT from a16.example.tld[xx.xxx.xxx.xxx]: 554 5.7.1 <[email protected]>: Relay access denied; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<a16.example.tld>
Jan 14 21:03:38 a20 postfix/smtpd[9753]: disconnect from a16.example.tld[xx.xxx.xxx.xxx] ehlo=2 starttls=1 mail=1 rcpt=0/1 data=0/1 rset=1 quit=1 commands=6/8
Jan 14 21:03:38 a20 psa-pc-remote[26474]: Message aborted.
Jan 14 21:03:38 a20 psa-pc-remote[26474]: Message aborted.

+------------------------------
Return mail

This is the mail system at host a16.example.tld.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<[email protected]>: host a20.example.tld[xx.xxx.xx.xxx] said: 554 5.7.1
<[email protected]>: Relay access denied (in reply to RCPT TO
command)


Reporting-MTA: dns; a16.example.tld
X-Postfix-Queue-ID: 05774453D4E
X-Postfix-Sender: rfc822; [email protected]
Arrival-Date: Thu, 14 Jan 2021 20:59:35 +0900 (JST)

Final-Recipient: rfc822; [email protected]
Original-Recipient: rfc822;[email protected]
Action: failed
Status: 5.7.1
Remote-MTA: dns; a20.example.tld
Diagnostic-Code: smtp; 554 5.7.1 <[email protected]>: Relay access denied
+------------------------------

Thank you.

 

[Bitpalast]

"Relay access denied" normally means that the sender has not properly authenticated himself at the SMTP server. For example, no login was done before the mail was sent.

 

[rik]

As follows, there seems to be no problem on the sending side.

I tried sending to postmaster@

[email protected](hostname a16.example.tld) --> a20.example.tld(Plesk Web Admin) --- Relay access denied
[email protected](hostname a16.example.tld) --> a19.example.tld(Plesk Web Admin) --- OK
[email protected](hostname a16.example.tld) --> a18.example.tld(Plesk Web Admin) --- OK
[email protected](hostname a16.example.tld) --> a17.example.tld(Plesk Host Ed.) --- OK
[email protected](hostname a16.example.tld) --> a16.example.tld(Plesk Host Ed.) --- OK

[email protected](hostname a18.example.tld) --> a20.example.tld(Plesk Web Admin) --- Relay access denied
[email protected](hostname a18.example.tld) --> a19.example.tld(Plesk Web Admin) --- OK
[email protected](hostname a18.example.tld) --> a18.example.tld(Plesk Web Admin) --- OK
[email protected](hostname a18.example.tld) --> a17.example.tld(Plesk Host Ed.) --- OK
[email protected](hostname a18.example.tld) --> a16.example.tld(Plesk Host Ed.) --- OK

Another email system
[email protected] --> a20.example.tld(Plesk Web Admin) --- Relay access denied
[email protected] --> a19.example.tld(Plesk Web Admin) --- OK
[email protected] --> a16.example.tld(Plesk Host Ed.) --- OK

[email protected] --> a20.example.tld(Plesk Web Admin) --- Relay access denied
[email protected] --> a19.example.tld(Plesk Web Admin) --- OK
[email protected] --> a18.example.tld(Plesk Web Admin) --- OK
[email protected] --> a17.example.tld(Plesk Host Ed.) --- OK
[email protected] --> a16.example.tld(Plesk Host Ed.) --- OK

Thank you so much.

 

[mow]

"Relay access denied" normally means that the sender has not properly authenticated himself at the SMTP server. For example, no login was done before the mail was sent.

Yes, but that is usually only relevant for the first mailserver that takes the submission from the MUA. After that, it means that there are discrepancies between DNS and host settings, e.g. a machine is listed as MX but doesn't know it is supposed to serve or relay that domain.
(And if you enable relaying, which you shouldn't do, you will end up with an error "Mail loop detected; MX points back to myself".)

 

[rik]

Resolved.

Tools & Settings > Server Settings > Full hostname

a20.example.tld --> another.example.tld [OK]
another.example.tld --> a20.example.tld [OK]

I changed it to a different hostname and then changed it back.
Now it is normal.
It seems to have been repaired.

Thank you very much for your help.