Rarely while working with assembles registered in Isolation mode as Sandbox, we get this error:
Error: “The communication object, System.ServiceModel.Channels.ServiceChannel, cannot be used for communication because it is in the Faulted state.”
Trace log file says: “The plug-in execution failed because no Sandbox Worker processes are currently available. Please try again. System.ServiceModel.CommunicationException”
There may be many possible reasons for getting this error, but few common points that should be checked which can fix the issue are:
Check for Microsoft Dynamics CRM Sandbox Processing Service. If stopped, start it.
If on-premises and security is not compromised, you can register the assembly in Isolation mode as “None” instead of “Sandbox”.
Check for .Net version used by the plugin and .Net version installed on server from control panel.