Symptoms
Authorization Failed
Diagnoses
When you have a form that uses a a endpoint assembly dll. The endpoint assembly is configured as serviceaccount. When running the form (that calls methods of the dll), using a given user (an administrator) it works ok. When using another user (testk2).
Error Marshalling SourceCode.SmartObjects.Runtime.SmartObjectClientServer.ExecuteInstance, Authorization Failed
Resolution
Check to see what permissions does the user have via both smart object administration and smartbox administration.