Cannot add Calendar, gives status:500 Internal Server Error

[leonsteber]

{"title":"An error occured: System.NullReferenceException","status":500,"detail":"Internal Server Error","traceId":"00-6f49b2cd083a22b01948255076c9154e-e771e040627e861f-00"}

Is this just me?

First time to try adding calendar as data source. I didn't get very far.  This happened after "Google AppSheet wants access to your Google Account "