Little background information;
I’m running mailcow on AWS with a Debian 9 instance. Debian 9 is almost EOL so my plan is to migrate into a Debian 11. Debian 9 is the original installation, was a fresh install at the time and regularly updated since then. There are around 10 domains with total roughly 100 mailboxes. This is a very low traffic mailserver, only for my private use. I also have apache reverse proxy configured. This used to work perfectly fine but sometime ago (maybe a year) something went wrong with the SSL. I’m getting invalid certificate warnings as I’m trying to add an email account to Thunderbird, but when I accept the exception all works OK.
New server: A Debian 11 AWS instance, in the same VPC and Subnet as the source, elastic IP moved from source to new.
I followed the instructions from official documentation. I installed docker, docker-compose and apache2 on the new server. Took a full backup on the source, moved to new server and did a restore. No errors during this process. After that I followed the Reverse Proxy documentation from the official docs. Edited the config as needed.
I can access web interface. Also send and receive emails using SOGo.
However,. now the mail accounts I already configured on Thunderbird says they can’t connect to the server. When I try to add a new account, initially it confirms my account details are correct but when I click add I get the same invalid certificate warning. Thunderbird thinking the certificate should be “mail.mymailserver.net:993” but what it receiving is “autoconfig.emaildomain.com” . When I accept the exception the warning comes back again and this time it expects “mymailserver.net” and when I view the certificate it is “mail.mymailserver.net”. I accept the exception again but from here Thunderbird says wrong credentials or error in mailserver config (or something similar).
I’m quite lost and I can’t figure out what I’m doing wrong. Obviously I have some incorrect configuration in my source server, this is why I’m getting the certificate warnings. And migrating with the faulty config causing issues.
Do you have any ideas what would be wrong?
Thank you for your help