Some wireless terminals cannot search for 2.4G signals

Traditional topology

A customer reported that some wireless terminals could not search for 2.4G signals, but could only search for 5G signals, mainly involving WA6620X and WA6630X.

After checking the configuration, it is found that the 2.4G radio is working properly and the channels are normal 1, 6, and 11, the number of access terminals and hidden SSID are not configured.. Further investigation revealed that the AP group was configured to disable probe detection response. It was suspected that some terminals mainly relied on the terminal network card to actively scan signals when scanning signals, and detected by sending probe messages. After the probe detection response was disabled, the AP would not respond to the terminal's probe detection request, and could only periodically send beacons, and the terminal would passively scan signals.

 #
wlan ap-group XXX
vlan 1
broadcast-probe reply disable // probe response shutdown
radio 2.4g
radio 5g
radio 6g
......

The problem was solved by deleting the probe response function:

undo broadcast-probe reply disable