I have successfully added three personal gmail accounts to thunderbird, but cannot add my google business/workspace account. When i try to login, it says "Authentication Error". I had to recently upgrade my google workspace account with 2 factor authorization. I looked on the forums, and it described that i have to select Oauth2 as the "authentication method" - but it is not available on the drop down menu. I checked for my personal accounts - the oauth2 is there is an authentication method, just not when i try to login with the workspace account. I am relatively sure this is causing the issue, as google does not allow the normal logins from 3rd party clients. But I don't know why it is not there as an option for my workspace account.