I have the sam issue, but I found the solution - i think that temporary, becouse ESET should to fix it or refresh.
Go to Settings , Advanced... then search for SSL. You will see an option like LIST OF APPLICATIONS, WHICH ARE ...... FILTERING PROTOCOL SSL/TLS. Then Click Edit, search for Thunderbird and Edit it from Automatic to Ignore.
Problems with thunderbird and IMAPS
in ESET Endpoint Products
Posted · Edited by AJF
Hi
I have the sam issue, but I found the solution - i think that temporary, becouse ESET should to fix it or refresh.
Go to Settings , Advanced... then search for SSL. You will see an option like LIST OF APPLICATIONS, WHICH ARE ...... FILTERING PROTOCOL SSL/TLS. Then Click Edit, search for Thunderbird and Edit it from Automatic to Ignore.
Regards