Hi I have two Wireless LAN Controller version 4.2, and the 1131 access point. The WLC number is called WLC01 and the name of the second WLC is WLC02. In the access points the Primary Controller Name and the Secondary Controller Name are configured as WLC01 and WLC02. The problem is that when the WLC1 (for example) fails the access points are not re-register in the WLC01, these remain registered in the Secondary Controller. To resolve this problem I restart the access point and these are registered in your primary wireless controller.