Today all of a sudden I have users telling me they are getting this message and sure enough I am getting it as well.
Operations Dashboard for ArcGIS
There was a beta refresh today. The old dashboards that have been created from operation views are no longer supported and will need to be rebuilt. There's a lot that has changed from our previous beta release and the underlying architecture has been updated to support all of the new features that are now available in the dashboard items.
For more information regarding the beta update: