no DHCP FROM AP 10

hai,

i have ASG 525 version 8.301...

i tried Astaro AP 10 seperate interface on astaro named wireless interface with ip 172.16.100.1 and Enable DHCP for this interface from astaro.

AP 10 is up get the ip 172.16.100.4 and i can connect to access point with its SSID ASG-AP but my laptop not getting DHCP from AP 10....

actually the customer has one more DHCP interfaces.....

what could be reason why i am not getting the DHCP after connecting my laptop to the AP 10....

even with manual ip i could not able to ping the AP 10 (172.16.100.4)

thanks in advance....