The Aruba 125 access point show me il flags
Make sure the VLAN the access point is on has dhcp
Make sure the controller has an ip interface on that VLAN
Make sure control plane security is turned off:
(configuration> network> controller> control plane security> Disabled> Apply.
By CLI set: ADP enable
adp discovery {disable|enable} igmp-join {disable|enable} igmp-vlan <vlan>
(Aruba7030) [mynode] (config) #ADP discovery enable