First you need to logon to your webmail account via a browser. This is important because it's the only way to confirm the password you are entering is correct. * Please confirm you can access the webmail account. * Please post an image of the pop up error requesting password. If Thunderbird asks for password, it means the current saved server settings and/or password are not being accepted by the server. What server settings are you using? Let's check everything is correct. In Thunderbird Post images of the following: * 'Account Settings' > 'Server Settings' for the account * We need to see the top section - this will tell us the server type, server name, port, Connection Security and Authentication Method - you can blank out the user name. * Also post an image showing the 'Outgoing Server SMTP' settings. In Thunderbird * Help > Troubleshooting information * scroll down to 'Mail and News Accounts' section * Post image showing all the contents OR copy and paste all the data into this forum question. Some servers still permit the use of the same password as used to access webmail account. Other servers now insist you have to create a 'secure app password' for use when accessing server via a third party app. So a normal password will fail. Gmail, office365 and some yahoo servers insist on using Authentication Method : OAuth2, so once that has been set up entering a normal password is going to fail as it's not expected. As you can see knowing the server settings means we can offer better advise on passwords. If you use '''Xfinity''': Xfinity also requires the user to access webmail account and enable access to server for third party apps. So it's worth checking that has been selected. I have known people discover it was switched off. See image below as guide. Tell us if you use Xfinity. Do you normally allow Thunderbird to store /save passwords ?