You must map Smart Material users with the your authorization service. For example, if you are using SmartPlant API Manager (SAM) as your authorization service, you must map your materials system user with registered SAM users. To perform mapping navigate to the SAM application and add the user in the Smat Users group.
User's UserName (Unique identifier for this user) should be same in Smart Materials and SAM.
To add or manage users, refer to SAM documentation.