Cisco :: Avaya Phone Won't Talk With Server?

When I place the phone on a different subnet, registration failed. The connectivity between the two subnet should be working because I have a desktop computer hook up behind the Avaya phone and the computer can talk with the server without problemThe phone has gotten the IP from DHCP server can I can even ping the IP from phone server. but on the phone it shows "Discover 10.0.10.10" then reboot, again and again. 10.0.10.10 is the IP of phone server. And there is no firewall rules blocking the traffic between the two subnet.Like I said before, if I place the phone on the same subnet as the server it worked. The setting of the switch remain unchanged