When a FlexConnect AP changes to standalone mode, it means that the AP has lost or failed to establish CAPWAP connectivity with its Wireless LAN Controller (WLC). In this scenario, all controller-dependent activities stop working except for the Dynamic Frequency Selection (DFS). DFS is a mechanism that allows wireless LANs to use 5 GHz frequencies that are shared with radar systems. It is a part of the radio regulations applied to WLANs, and it is designed to avoid causing interference to radar systems.