facoty default them and make sure you connect them in the same L2 domain. They wil then find the ZD and pull the config(if you have automatc approval enabled. Otherwise you will need to approve them first in your ZD)
After factory default there is no connection to the ZD. But i also connect a AP who have worked in another network and these AP's connected without any problem.
After this i knew what happened with the AP which cannot connect to the ZD. They where configured to a Virtual ZoneDirector before i connected them to a ZD1000. So i think there is the problem. But the factory settings do not overrule the configuration from the Virtual ZD
If the APs were managed by a vSZ or having a vSZ firmware on it, then please upgrade the APs to 104.x AP standalone firmware before joining them to the ZoneDirector.