Symptoms

We are Using K2 App IT REST Service Broker to get data and it errors with: Broker Execution Failed. (Inner: Object Reference not set to an instance of an object.)
 

Diagnoses

This same service instance is working in another environment.
 

Resolution

Performing a refresh of the Service instance via the K2 Management page resolved the issue. Perhaps there was an update to the definition of this REST web service in which one environment see while the other did not; refreshing the service instance would sync the service instance with those changes made to the REST web service.