The mode that is exclusively used for troubleshooting among the options provided is Sniffer mode.
In Sniffer mode, the access point (AP) captures and analyzes traffic on the network for diagnostic purposes, making it a valuable tool for identifying issues and performing troubleshooting tasks. The other modes mentioned (Bridge, Local, and Flexconnect) have their own specific purposes related to network design and functionality rather than solely for troubleshooting.