I have Thunderbird 60.9.1 on Windows 7 32 bit and it works. I installed 102.6.1 on Windows 11 64 bit and I am having problems. After installation I copied the entire contents of the "profile" from the old system to the new system's profile and I have my folders, mails, accounts, etc. - just like I expect The problem involves connecting to a LOCAL mail server. Connection to Gmail, another private server somewhere in the world and even AOL - all work fine. The local server (Linux) connects only sporadically. Upon startup I get the totally unhelpful error box ""cannot connect to mail server {name}. Connection refused" NATURALLY it doesn't list the connection dialog or anything that would help. On the server, I go to the mail log for POP3 and it lists the connection - then NO activity - and then disconnection. If I fire up the Windows 7 server and Thunderbird, the mail comes in just fine. The failed connection is: 192.168.0.10 Port 110 {username} Connection Security {none} Normal password {transmitted insecurly} ** THE EXACT SAME SETTINGS THAT FUNCTION FLAWLESSLY ON THE 32 BIT version. Windows firewall is deactivated, there is no AV program installed (yet) I's wondering if there is a log file available that is just not documented?