error msg on WLC

[J_Vansen_S]

I am trying to place my LAP on a different subnet as of my WLC, this is the error msg i got

Received LWAPP DISCOVERY REQUEST from AP 00:0b:85:64:cc:90 to ff:ff:ff:ff:ff:ff on port '4'

Received a Discovery-Request on an unsupported VLAN 18

Did i miss anything on my WLC configuration

[ivillegas]

Make sure the VLAN 18 is allowed on the trunk port between WLC and the switch and that the VLAN is present in the database of the switch.