Set External PV's node throwing error :The user account for com.appiancorp.suiteapi.process.exceptions.InvalidProcessException: Does not exist: Process could not be created. (APNX-1-4160-000)

We are using Set External PV's node from plugin Get and Set Process Variables but it is throwing error as invalid process exception. Please let us know if any knowledge articles or documentation we can get to understand the functionality and to counter any missing loopholes.