So as I recall, there may not be very many users of Thunderbird here at TS, but I thought I'd report on an issue I am presently experiencing. Ever since Gmail and Google went to two-factor identification, Thunderbird won't accept the password any more. I've checked all my settings and everything seems to be in order. In the meanwhile, I've set up Apple Mail to handle my Gmail account and it's working fine.
Any bright ideas? Running Catalina 10.15.7 on a 2020 MBP.
TIA,
Chris