This counts failures that occurred while trying to add an MVRP message into the internal MVRP processing queue. Admins check this to spot resource pressure inside the MVRP subsystem, since a growing count suggests the switch can't keep up with the volume of VLAN registration events it needs to process. For example, a spike in this counter during a mass VLAN reconfiguration event indicates the switch's MVRP queue is being overwhelmed by the burst of registration messages.