Try removing your email profile and readding it.
Before doing this, make sure you haven’t saved any emails locally to your machine, and if you have, make sure you save them somewhere else because doing this will erase any emails saved locally.
It will also take some time to get all of your emails to sync back over (could take a couple of minutes up to hours depending on how many emails you have).
To remove your email profile (make sure you close outlook first)- click on start->control panel->user accounts->mail (Microsoft outlook 2016)->show profiles->delete the one that says “Outlook”-> add a new profile-> rename it to “Outlook” or “Office 365”->open outlook again->resign in with your credentials.