Mac Mail hangs trying to add new mail account
I am attempting to add a new Mail account, and after filling out the email address, password and IMAP incoming and outgoing mail server, I got a spinning wheel forever. I tried the same thing on my wife's Macbook and it worked. What is happening? The Mail Connection Doctor shows nothing, and I already searched my Keychain Access for passwords/other things to clean out to no avail.
MacBook Pro 15", macOS 10.14