No Emails anymore via Thunderbird (bad certificate: SSL alert number 42)

Webmin
1
SYSTEM INFORMATION
OS type and version Ubuntu Linux 20.04.6
Webmin version 2.021
Usermin version 1.861
Virtualmin version 7.7
Theme version 20.21
Package updates All installed packages are up to date

Since some day’s I don’t get EMails via Thunderbird Emai-Client.
At the Server-Logs I found something like that if I try to fetch Emails from server:

Jun 17 16:22:17 xst02 dovecot: imap-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=95.122.126.244, lip=178.47.141.28, TLS handshaking: SSL_accept() failed: error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate: SSL alert number 42, session=<k1tTB1T+2N9f3aBC>

Server is configured to use letsencrypt certificates.

2

I wonder if this TLS related (the move from TLS 1.0 to 1.2 for ssl connections (IIRC I read something about a change to Postfix)? There have also been updates to T’bird recently that have caused big problems with accounts created without STARTTTLS

3

Do you have any suggestion how to test or fix this issue?

4

IIRC there was a post on here a while back
As for the STARTTTLS issue in T’bird it is causing me no end of problems. It seems to be with users who have previously used a lower security and have emails saved/archived.

5

Thanks for your answer, but I don’t see something valuable for me to use it for fixing the issue.
Can you point me to the IIRC where you read it, or can give any other hints how to test / fix this issue?

6

The issue is at least at TB side, as you said.
I’ve changed server-settings to connect without SSL and re-change it to use SSL.
Then I got a notification, that the certificat is unsecure. I add an exception to allow this, and now it work again.

7

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.