"Error invoking Hub Method" when starting PPW
Symptoms
The following error appears when starting PPW:
Error: There was an error invoking Hub method 'taskactivationstatus.join'.
Clicking OK clears the message, but it appears the next time PPW is started.
Reason
This error can occur when Rapid-fail protection errors in the WebSocket application pool in IIS exceed the configured limit and cause the application pool to be stopped.
Resolution
Restart the WebSocket application pool on IIS.