OK, I noticed with the ever changing Google's system, that the auto configuration just don't work in TB, it kept on displaying 'configuration could not be verified is the username or password wrong' and after spending hours checking this and that, Googling the error, and found everything is perfect, the pop3 and smtp addresses were correct, SSL was set, and the ports were perfect, and still it came up with that error, even though both my username and password for Gmail works on my Android tablet, my phone, my PC, my wife's PC too, and my Gmail pop3 settings were enabled since 2005, so there was literally nothing wrong with the Gmail settings, so,,,,I thought I would try the TB manual configuration, and reset everything to my Gmail account, and when I clicked Done, yep, sure enough up came that error, so just out of curiosity, I clicked on account 'Advanced Configuration' in TB, and it shows multiple text boxes and some drop downs, I left everything but the security and password method to default, and the security I set to auto and the password method I set to auto, and then when I clicked on 'Re-Test' a window popped up saying the certificate was issued by a none-trusted authority, but I as I knew Gmail is a reputable company, I clicked on the link at the bottom of that window to accept the certificate, and lo and behold, TB logged into my Gmail and started downloading emails.

Sooo, for anyone that is having the same problem, it is probably because TB rejects what it considers an invalid SSL certificate from Google, even though the certificate is valid, and refused further logins.