OS X Mail app doesn't display incoming server settings
My Mail app is behaving oddly. I'm having trouble connecting to one of my accounts, and it seems to be because it's rejecting the password. When I went to try updating it in the server settings, the incoming server settings simply aren't there. It only shows a single line for the outgoing server setting. Anyone have any idea what's going on? Can I reinstall Mail without losing my large cache of IMAP messages, and more importantly, my old POP messages?
MacBook Pro 15", macOS 10.13