I upgraded all of 6 my 2821 Voice Gateway routers to 12.4(11)XW3 to prepare for more secure SSH access.
In order to enable SSH I input ip domain-name.
I noticed that CallManager displayed unregistered for these MGCP controlled E1 controllers.
I removed the ip domain-name and the gateways re-registered with CallManager.
Has anyone an answer to this please?