When I have a poor internet connection, Mac Mail somehow switches into a mode when it no longer can connect to my Exchange email account (no problem with IMAP). In this answer it is suggested that Mail attempts to automatically manage account settings should problems (such as a poor connection) occur, which may it ending up with invalid account settings.
I have now switched this off, but the account is still not working. How can I reset it to the appropriate settings (without deleting and re-instating it – as suggested here – which would re-load ~10000 emails, which I rather avoid)?
I should say that I'm running macOS 10.12.6.