I have been using Thunderbird for over 20 years, both at my former job and personally. I have never had a failed login. I have read lots of the forum questions for failed logins. I have tried following instructions in "Did your ability to receive mail suddenly stop? Was it working before?" I had to use my employee account (I am retired) to receive the code to sign in to this site. My personal Thunderbird account is nanwoo@comcast.net, but since I can't login to that account, I couldn't receive the code there. When I closed and and reopened Thunderbird, the whole imap://imap.comcast.net account disappeared. It now has reappeared, but I don't know if I need to change my password to my new Comcast password (they made me do it). If so, how do I do that? Right now, the password is the one I've been using on my Thunderbird account. I am old and confused. I am not a programmer. This is very stressful and time consuming. You can't email me when someone answers this question, because I can't login to my email! I will leave this window open until I get an answer.