Microsoft just took over your PC with new Outlook. Now outgoing is failing. You’re using cPanel.
Here are some of the errors:
We couldn't deliver your message. Original message details Created date: 11/25/2024 6:35:10 AM Sender address: user@example.com Recipient addresses: recipient@domain.com Subject: test Technical details SmtpSubmissionPermanent5XXException: Smtp submission failed. Server 'mail.example.com' Port '465'. --> Unexpected SMTP server response. Expected: 235, actual: 535, whole response: 535 Incorrect authentication data Failure code: eff7
However, when you go to Control Panel, Mail, and test there, it works.
Mistake #1
New Outlook doesn’t use the control panel icon anymore. Right click on an account, and find settings there.
You get the client’s IP address.
Next, you look in the WHM log file using:
tail -f /var/log/exim_mainlog | grep ip_address
Mistake #2
New Outlook has bastardised your sending and everything is now going via Microsoft’s cloud.
Next, you improve the tail command to include some Microsoft ranges (52.98):
tail -f /var/log/exim_mainlog | egrep "ip_address|user@|52.98"
Next, you start seeing the detail required.
2024-11-25 08:50:07 SMTP connection from [a.b.c.d]:56001 (TCP/IP connection count = 3) 2024-11-25 08:50:07 no host name found for IP address a.b.c.d 2024-11-25 08:50:08 1tFSv6-00000002Oge-2bQI <= user@example.com H=(THEPC) [a.b.c.d]:56001 P=esmtpsa X=TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256 CV=no A=dovecot_login:user@example.com S=1227 T="Microsoft Outlook Test Message" for user@example.com 2024-11-25 08:50:08 TLS error (SSL_read): on connection from (THEPC) [a.b.c.d]:56001 error:0A000126:SSL routines::unexpected eof while reading 2024-11-25 08:50:08 SMTP connection from (THEPC) [a.b.c.d]:56001 lost D=0s
And this:
2024-11-25 08:54:49 dovecot_login authenticator failed for (CWLP123MB5402.GBRP123.PROD.OUTLOOK.COM) [52.98.170.21]:15117: 535 Incorrect authentication data (set_id=user@example.com)
Solution
Double check the outgoing SMTP username. In this case, Microsoft broke it like so:
user@example.comexamp.com