I had Thunderbird on my Windows 10 computer. I bought a new Windows 11 computer and downloaded Thunderbird. When I try to set up my email account, I provide my full name (not my Thunderbird user name) and email address. The next screen has the message "Configuration found in Mozilla ISPDB ". I clicked on IMAP and hit continue. The next screen I type in my password for my Spectrum mail account. I have confirmed that the password works went I log onto the Spectrum website. The next screen has the Authentication error "Unable to log in at server. Probably wrong configuration, username or password.". I've also tried using my Thunderbird user name and Password instead of my full name and Spectrum password with the same results. I know my Thunderbird user name is correct but I can't be 100% sure that my Thunderbird password is correct. I'm not sure if this matters but my email has the has the extension ----@socal.rr.com. This was assigned to me by my original email provider, which was Time Warner Cable. Spectrum bought Time Warner Cable a few years ago and I think Spectrum uses a different extension.