I'm having the same problem as everyone else here. So frustrating. I just deleted the autodiscover records hoping it would work...it didn't. I've tried absolutely everything I can think of, and every time I go to re-add my account I get the message that my Microsoft account needs to be reconnected. It works fine on my two laptops at home, but I cannot get it added back to my desktop at work. At one point I even uninstalled Office 2016, installed Office 2013, added my account and it worked. As soon as I upgraded Office to 2016, thinking an in-place upgrade when it was working would keep the account connected, I got the message to reconnect my account. I have no idea what to try next. I've tried contacting Microsoft support about the issue and they were clueless and they eventually just disconnected the session because they couldn't figure it out.