Just coming back to this issue. We have just upgraded to 6.3 and we have a large number of APs doing this again. I think it might be realated to the settings I use to teminate the APs.
When I provision an AP, I set the IP address of the Master Contoller as our master (12.3) even if the AP profile points it to our slave (12.3). The reason is an engineer suggested we do this, rather than code the AP to terminate on 12.6, a brest practise approach and let the AP profile push the units to the approriate controller.
I have found if I reprovision the AP with the slave as its master ip address it does come back up. Looking at the list of APs down, some are showing .3 as their controller some as .6 for the same site (same AP group).
So the question is, if an AP is up with an IP address and is not terminated, how can I change the IP address to terminate from 12.3 to 12.6 remotely? Or should I change the AP profile? We use the internal database for APs and I have checked the usernames for the APs are on both and there are enough licenses.