I have multiple gmail accounts. I can add all but one to Thunderbird. When I try to input the email address/password (the same that I use in the Firefox web browser), it says, "Configuration could not be verified -- is the username or password wrong?" I have verified that the email address and password are correct, that the account is set to enable IMAP, that the port number for incoming messages is 993 and is set to SSL/TLS. I have even tried going to https://accounts.google.com/DisplayUnlockCaptcha to reset the account to enable it to be added (as that's one of the suggestions I've seen online). No joy. Sometimes, after going through the process, I will get the same configuration can't e verified message and it appears that the account is added but when I try to click on the inbox, it asks for the password again. It will still fail to connect. I also get a pop up error message that says, Thunderbird Alert from account <email address>: Please log in via your web browser: http://support.google.com/mail/accounts/bin/answer.py?answer-78754 (Failure)