This looks like a repeat of https://support.mozilla.org/en-US/questions/1569051 please stay with one thread. thank you.

it's just the email password that's the problem thank you

Repeating what David said in the other topic (which is now locked) ...

If you need/want to reset the account password, you must do that at the email host website. If your intent is to reset Thunderbird's stored password, try this - click to settings, privacy&security, click the savedpasswords button and then showpasswords and then highlight the rows for the account and delete them. that should allow for a password prompt