We are a small computer support company with onsite exchange 2016. Two of our computers with Windows 10 and Outlook 2016 from time to time disconnect from the exchange server and won't reconnect unless you restart the computer. They will stay connected for hours, sometimes for days, but once the disconnect occurs they will not reconnect without restarting the computer. When the disconnect occurs GetAppManifests failed appears in the event log. Restarting Outlook in normal or safe mode gives the same error. After a computer restart, GetAppManifests succeeds and Outlook works normally until after several/many hours it suddenly disconnects again.