Yahoo usually uses Authentication Method Oauth2. After updating a password in the yahoo webmail account, you would need to access the stored passwords in thunderbird and remove them. * Settings > Privacy & Security' * under Passwords section * click on 'SAved Passwords' * clickon 'Show Passwords' * Look for any line that mentions the 'username' = email address of account. * You may see more than one line for that username. * Select the lines and click on 'Remove'. * click on 'Close' * Exit and restart Thunderbird At the prompt enter the new password. Enter it. You may get a prompt to confirm your password etc and to select to allow Thunderbird access to server. ''re : I get the message:-If you still can't sign in try a different device. My wife can sign in on her Android phone but I can't'' Andriod phone is not relevant in this instance as you are talking about the desktop Thunderbird. That part does not sound like Thunderbird desktop....wait a minute...are you talking about you are in the process of adding the account and get a pop up window that should ask you to confirm you are you and to allow Thunderbird access to yahoo server? It would have helped if you uploaded an image of this error. Please confirm Using a browser - Can you logon to your yahoo webmail account using the new password? Is your wife accessing the exact same email address on her phone ? If yes, then tell her to switch off the phone, so you can retry - I am assuming she has already updated the password.