Wlan1 not getting IP

Hi…
I am trying to connect to my cable Wifi modem through RB411. Layer 2 connectivity is established but Wlan 1 is not getting an IP address from my cable Wifi modem. I have set DHCP client and interface as Wlan1 but the status is showing as “Searching”. Any one knows what to do?

PS: My cable wifi is issuing IP address to other PC’s but not to the RB411.

Regards