In my case, the AP's works with a SSID which is public and other SSID that are only for employee, that's the reason because we can't turn off the 2.4GHZ band because customers who visit the bussines use old cel phones or devices. Also, I already use a RF Profile, it's the basic Indoor Profile, We have around 30 AP's but only 4 AP's has the speed of negotiation reduced, I already try to cycle the switch port, reboot the AP, run the cable test, and force the speed, but the issue still persist.
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