I have a domain for a business and web hosting. Email accounts come with the hosting and I set up several. At some point, I began to get pop-ups asking for my logon credentials. Although they were annoying, I put up with them for a time. I thought a password problem might be causing it, so I changed the password and made sure it was the same both on the server and in Thunderbird. Eventually, this situation became more than a nuisance and (after saving the messages off-line) I deleted the email account from both Thunderbird and the server. This did not work and I still gat the pop-up messages! I have consulted with the web hosting support staff and they assure me that the account is no longer on the server. Obviously, there is some vestige of the deleted account in Thunderbird someplace and it is causing the program to attempt to sign in to the server to access the no longer existing account. This, in turn, causes the server to request the credentials for the deleted account, resulting in the pop-up messages. How do I get rid of this?