001998: The subnetwork system diagram <value> is managed by the system, it cannot be deleted.


The diagram you are trying to delete is a subnetwork system diagram. Subnetwork system diagrams are particular diagrams that cannot be deleted by any users. Only the utility network owner can delete them.


You can generate such a diagram yourself from the result of the trace returned for the same subnetwork. Then, you will have full access on this diagram.