Adding another voice to the mix. My charter.net email stopped working a couple of days ago in new Outlook. I tried fixing, re-entering PW, etc... but nothing worked. No sending and no receiving on that email, while three other email accounts still work.
After reading all these comments - I realize I'll likely just have to wait for Microsoft to fix its update bug. It's incredibly inconvenient to not be able to get all my accounts in Outlook for sure!