Background use Firefox. am stuck in irresolvable gmail problem loop with passwords (apparently none are valid) asking for a passcode gets the code sent to an email account which is different but, by now, inaccessible because its password has become invalid. After long time thrashing around trying to solve this downloaded Thunderbird & in response to question of where to put/link I replied Firefox whereupon it picked up something like fred@gmail.com as the user!