Two months ago I had to install Thunderbird as New and I can't access my personal Gmail account. Everytime it fails to connect to gmail servers (Error 400). Two others, also Gmail work fine and in other programs like Vivaldi Mail, Outlook, Windows Mail it works seamlessly, but for more than 20 years I was using my Favourite Thunderbird. The problem persists even after todays upgrade. I tried even with portable version and tripple-checked the password and Servers setting. I ran out of ideas. Can you help? Dare