The only place you can create, modify etc passwords is in the webmail account for the email address. That means you need to use a browser and try to logon to the account. There should be a 'forgotten password' link which you need to use and follow the instructions to regain access to the account. Once you have gained access you can reset the password. Then in Thunderbird, you use that newly created password for the account. It is saved here: * Menu icon > Settings > Privacy & Security * Under 'Passwords' section * click on 'Saved Passwords' * click on 'Show Passwords' If the account is already listed: * right click on each appropriate line and choose 'Edit Password'. * Completely clear all contents and carefully type in new password. * Click on 'Close' then restart Thunderbird. If account is not listed: Retstart Thunderbird and at the prompt enter the new password. Make sure the checkbox to 'Remember Password' is selected before you click on 'OK'