"Due to organizational policies, you can't access these resources"

I attempted to connect to my Project Online instance today with Project 2016 using my administrator account and could not. I received a short message stating "Due to organizational policies, you can't access these resources".  I was using a virtual machine in my test bed, so attempted the same on my workstation and found I could connect.

I cleared the cache from Project 2016 and was able to connect again: File > Options > Save > Clean Up Cache.