re :I changed my password on e-mail provider server. Did you then update/edit the stored password in Thunderbird ? * Settings > Privacy & Security * Scroll down to 'Passwords' section * click on 'Saved Passwords' * Click on 'Show Passwords' You may get asked for a password. * If you had previously setup to use a 'Primary Password' in Thunderbird then enter that password. * If you have not set up to use 'Primary Password' then....when you start up computer and enter password to Logon to your User Account to see desktop - that is the password you need to enter. Then you may have 2 lines for the mail account incoming (imap://... or mailbox://...) and also outgoing (smtp://...) - * Right click on each line in turn and select 'Edit Password' * Completely clear the contents and then carefully type in the new password you set up in the webmail account - email provider server. * After doing both incoming and outgoing, clickon 'Close' Exit Thunderbird and allow a few moments for background processes to complete Restart Thunderbird and it will use those new passwords.