NCX2500 - AP Disconnected randomly

Hello at all, 
I have a problem with the Gateway Controller NCX2500. We have this gateway since 2014 and we haven't problem since the last year.
The NCX control 21 Access Point (4 NWA5123-AC and 17 NWA5121NC)
But in the last year we have some problem about frequently random disconnections in our devices and i cannot found the problem.
I have read about the deactivation of "DCS Client Aware" and activation of "Scheduling DCS" and i have update the firmware of controller at the last version (V6.10(AAIG.2))
The log file taking about a lot of Disassociation (1:UNSPECIFIED, 3:DEAUTH_LEAVING)
Can you help me please? Thank you so much