I tried all of the things I could find online and nothing helped getting Outlook to reconnect to the server. The one thing that I had seen, which caused me great fear, was instructions to delete my Outlook.com account and then add it back in. As a last resort I did this then got an error that it would not reconnect to my .ost files until I had reconnected to the Outlook.com server. By stopping and restarting Outlook it reestablished connection and spent a while updating and is now connected again. I hope this is not a continuing problem!