Symantec Management Platform (SMP) server or Task Servers refuse to acknowledge a manage agent when it tries to register for tasks.
Failed to call TS method 'RegisterClient'. Connection refused from unmanaged clients.
This is a known issue that occurs when the data in the secure storage folder contains a GUID that the agent is no longer using.
The Secure Storage folder is is labeled Ldb and is located here:
Follow these steps top resolve: