Gmail is making everyone change from Password Authentication to OAuth2 Authentication. It worked on one of my Window 10 laptops, but not the other. I have matched every single setting that I can find, but the new computer will not connect to Gmail - I get a 400 error. I noticed that even though I selected SSL/TLS under "Servers and Settings", in the "Outgoing Server SMTP" menu, it lists STARTTLS for the Connection Security - using port 587, on the computer with the error. On the computer that works both places list SSL/TLS - using port 465. Is that the problem? If so how do I fix it? If not, what can I do? I have uninstalled and reinstalled Thunderbird on the second computer three times now. I also spent hours with the Google Workspace AI - checking every possibility that was mentioned and nothing helped. Please help me. Thank you!