Understanding Error Message

[FlorinBuffet]

Hi there
When i try to send an email from a specific client i get this error:
2025-02-26 07:03:24 +0000 WARN Authentication failure for 162.55.4.xxx (no server found matching [email protected]) trace_id=8SHANBBU component=smtp-server
Of course the obsfucation from ip and email was done by me afterwards.
The E-Mail [email protected] has been used as a username in the client.
Can you tell me how to fix that?
From other clients it works.
Best Regards
Florin

[willpower232]

Presumably you aren't seeing this error message in Postal so your client is failing to get to Postal at all?

If you aren't connecting directly to Postal then I can only presume that mydomain.com doesn't have the right MX records perhaps?

[willpower232]

Are they all sending to the same domain or different ones? Can you see the error message if you expand the details in the Postal UI?

[FlorinBuffet]

All are sending from exactly the same email adress.
Where should i be able to find the details in the Postal UI? The E-Mail never gets accepted into postal which means is does not even appear there.

Here my configuration:
The Service trying to send a mail:

The credential configuration of postal:

The proof that other emails get sent:

And the log file of smtp-worker:

2025-02-26 19:41:39 +0000 DEBUG  Client identified as 162.55.xxx.xxx trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  <= EHLO support.mydomain.com trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  => 250-My capabilities are trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  => 250-STARTTLS trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  => 250 AUTH CRAM-MD5 PLAIN LOGIN trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  <= STARTTLS trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  => 220 Ready to start TLS trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  <= EHLO support.mydomain.com trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  => 250-My capabilities are trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  => 250 AUTH CRAM-MD5 PLAIN LOGIN trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  <= AUTH CRAM-MD5 trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  => 334 PDhiOGI4ODNkMmQ3MTMwYzVlZjAzQHBvc3RhbC5idWZmZXRpdHNlcnZpY2VzLmNoPg== trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  <= bm9yZXBseUBidWZmZXRpdHNlcnZpY2VzLmNoIDU1NWJmNjQyMWUxOWJlM2MxOTFiNDUyNzE2MWQ4ZDVj trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 WARN   Authentication failure for 162.55.xxx.xxx (no server found matching [email protected]) trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  => 535 Denied trace_id=IGFJAKYJ component=smtp-server
2025-02-26 19:41:39 +0000 DEBUG  Connection closed trace_id=IGFJAKYJ component=smtp-server

[willpower232]

no server found matching [email protected]

I presume this means you haven't added mydomain.com on the domains page?

[FlorinBuffet]

No, but i found the issue now by diving into log files, a bit of code and the documentation, in which i found the issue. The important part in the log-file is:
AUTH CRAM-MD5

According do the documentation (and then i worked), you have to provide a username for CRAM-MD5, which of course i just did as usual with an email adress. But the documentation tells: organisation_server
And then it worked.

[willpower232]

Ah yes, this is the one login method which requires a specific username, good spot.