There are a number of reasons why an AP650 would not adopt.
1) As in the previous response, the release on the controller and AP is important. If the AP in on Ver 4.X code and the Controller is on 5.4 or better, there is a sequence that needs to be followed to upgrade them. Please see your RELEASE NOTES.
2) How are you adopting. If the APs are in the same Broadcast domain, they will try to adopt over LAYER 2. If they are on a different subnet, you will need the set the CONTROLLER HOST variable on the AP to point back to the controller
3) If you are pushing a configuration to the AP that causes it to loose ADOPTION to the controller, the AP will revert back to its' last known good configuration
4) Do you have sufficient licenses