Call Manger Gateway problem

Hello,

I have configured a 2600 cisco router as a gateway H.323. I used the usual way to configure this : Like Devices – Add a new device-Gateway . Then I choosed a H.323 with Device Protocol H.225.
As Device Name I entered the Ip addres of the gateway, which I have configured manually.

I can also see my configured gateway in the device list with ip addres, name, device pool…
But why I still have a status “unknown” ???
Has anyone an idea ?