No, that was not done. What about this: We are low on DHCP leases. It seems that when we dive below a certain percentage available, say 10%, clients connecting via the WAP will not be issued a DHCP lease. Is this possible?
Your back to basic trouble shooting, cna you ping the DHCP sever from the AP's or vice versa, does the route still exist. was a DHCP helper removed. are the clients authenticating and assoc to with an AP.
save the config from one AP or use a spare AP to test with with no encrypition and no authentication. in other words back to basics.
If you are using a WLC same list different device.
I agree the DNCP server should hand out addresses untill they are gone.