In Mail's preferences, I have deleted duplicate SMTP servers. In the list that comes up, they can be removed and stay removed, yet when using the Connection Doctor in Mail, the SMTP servers remain -- after quitting Mail, logging out, or restarting. Bug?
Mac mini, macOS 10.14
Are you certain they are duplicates that you are seeing in the Connection Doctor window? Not only does that window show both SMTP and IMAP accounts which are set up for each mail server, but they also show every single account you have set up -- by actual email address -- for each type of account as well. It might be helpful to extend the Connection Doctor window, and if need be, widen the "Account Name" column, in order to make sure you are seeing the full address.
Are you certain they are duplicates that you are seeing in the Connection Doctor window? Not only does that window show both SMTP and IMAP accounts which are set up for each mail server, but they also show every single account you have set up -- by actual email address -- for each type of account as well. It might be helpful to extend the Connection Doctor window, and if need be, widen the "Account Name" column, in order to make sure you are seeing the full address.
SMTP persistence after removal
