I get this error message occasionally. This is from the Windows Event Log. It seems to occur after a long period of inactivity - in other words, the user is logged in, but steps away from the computer for a period of time and then comes back.
WebHost failed to process a request.
Sender Information: System.ServiceModel.ServiceHostingEnvironment+HostingManager/58366981
Exception: System.ServiceModel.ServiceActivationException: The service '/EntityServer.svc' cannot be activated due to an exception during compilation. The exception message is: Object reference not set to an instance of an object.. ---> System.NullReferenceException: Object reference not set to an instance of an object.
at IdeaBlade.EntityModel.Server.EntityServerHostFactory.CreateServiceHost(String constructorString, Uri[] baseAddresses)
at System.ServiceModel.ServiceHostingEnvironment.HostingManager.CreateService(String normalizedVirtualPath)
at System.ServiceModel.ServiceHostingEnvironment.HostingManager.ActivateService(String normalizedVirtualPath)
at System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath)
--- End of inner exception stack trace ---
at System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath)
at System.ServiceModel.ServiceHostingEnvironment.EnsureServiceAvailableFast(String relativeVirtualPath)
Process Name: w3wp
Process ID: 6096