1. Thunderbird was working fine with my Gmail acct for months, then was unable to send a message, but can still receive incoming messages. 2. I was asked to re-enter my password and this did not fix the problem. 3. I went to Gmail online and logged in to verify my password had not changed. Success. 4. I reset password in Thunderbird, but still couldn't send test message to myself. 5. I deleted account in Thunderbird. Then I added a different Gmail acct that was not in Tbird. Success. Then I sent test email, success. 6. Then I re-added the original Gmail acct, Failure! It found the correct settings automatically, but when it tried to verify password, it failed. I repeated entering the password several times, but still failure. 7. WIN7 64bit HP, Tbird 24.4.0 8. All other AOL accts work fine on Tbird.