I use Thunderbird on my desktop and a few internal tools that are meant for sending out emails to users. I keep getting issues where its either constantly failing to connect to my mail server or its having some type of auth issue.
From my application.
Checklist:
- I used dig and dmarc, spf and dkim settings came back fine!
- IP is not blacklisted.
- UFW ports are open because sometimes it works.
- Passwords are fine
I might have thought it could have been an SSL/TSL thing? I did find port 587 has no cert. I don’t know what mailcow settings are I couldnt find any documentation. Does it need to be pushed to users? And its not doing it.
sudo openssl s_client -connect localhost:587 -starttls smtp
CONNECTED(00000003)
Didn't find STARTTLS in server response, trying anyway...
write:errno=32
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read 0 bytes and written 23 bytes
Verification: OK
---
New, (NONE), Cipher is (NONE)
Secure Renegotiation IS NOT supported
Compression: NONE
Expansion: NONE
No ALPN negotiated
Early data was not sent
Verify return code: 0 (ok)
---
3: Connection: opening to mail.mydomain.com:587, timeout=300, options=array()
3: Connection: opened
2: SERVER -> CLIENT: 220 mail.mydomain.com ESMTP Postcow
1: CLIENT -> SERVER: EHLO hbt.mydomain.com
2: SERVER -> CLIENT: 250-mail.mydomain.com
250-PIPELINING
250-SIZE 104857600
250-ETRN
250-STARTTLS
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
1: CLIENT -> SERVER: STARTTLS
2: SERVER -> CLIENT: 220 2.0.0 Ready to start TLS
1: CLIENT -> SERVER: EHLO hbt.mydomain.com
2: SERVER -> CLIENT: 250-mail.mydomain.com
250-PIPELINING
250-SIZE 104857600
250-ETRN
250-AUTH PLAIN LOGIN
250-AUTH=PLAIN LOGIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
1: CLIENT -> SERVER: AUTH LOGIN
2: SERVER -> CLIENT: 334 VXNlcm5hhWS5
1: CLIENT -> SERVER: ---obfuscated---
2: SERVER -> CLIENT: 334 UGFzc3dvfbnT
1: CLIENT -> SERVER: ---obfuscated---
2: SERVER -> CLIENT: 535 5.7.8 Error: authentication failed: (reason unavailable)
1: SMTP ERROR: Password command failed: 535 5.7.8 Error: authentication failed: (reason unavailable)
3: SMTP Error: Could not authenticate.
1: CLIENT -> SERVER: QUIT
2: SERVER -> CLIENT: 221 2.0.0 Bye
3: Connection: closed
3: SMTP Error: Could not authenticate.