You set replies by accessing this forum in a browser. The password can only be set/modified etc whilst logged onto the webmail account. Then you can update the stored password for both incoming and outgoing smtp. Men icon > Preferences or 'Settings' if using v102* > Privacy & Security Scroll to 'Passwords' section click on 'Saved Passwords Click on 'Show Passwords' You will have an incoming line either mailbox:// or imap:// You will also have an outgoing line smtp://... The password you use to access the webmail account is the same password you use in Thunderbird for both incoming and outgoing. It is obviously set up correctly for the incoming otherwise you would be receiving emails. Right click on the smtp:// line for the btmail account/email address and select 'Edit Password' Completely clear the old password. Carefully type in the correct password - make sure the 'Caps Lock' key is not switched on. click on 'Close'. Exit Thunderbird - wait a few moments for background processes to complete and then restart Thunderbird. Allow Thunderbird to check for new mail before atempting to send an email.