2GHz network: group key exchange timeout.
Looks like clients didn't get the WPA/WPA2 key-change information. They will stop ALL being able to encrypt/decrypt properly.
https://www.techwalla.com/articles/what ... y-interval
"group key exchange timeout" is in many posts in this forum, and is all over the internet for other brands.
I did not find a proper workaround or fix.
If group key updates are sent via broadcast/multicast there is quite a possibility this is missed by some or all clients.
Broadcast/multicast uses the low basic-rate interface rate, to be sure to reach all clients without fault.
However with broadcast/multicast there is NO feedback, so there are NO retries like with unicast.
Unicast can survive glitches in the wifi-ether, because it resends as needed. Broadcast/multicast will fail if disturbed !
Some AP operators rise the lowest basic rate higher than 6Mbps, to save some air-time for beacons. However higher basic-rates will fail more often.
Setting the "Group Key Update" interval in the security profile higher than the default 5 minutes, will reduce the problem.
1 hour and longer is not uncommon ! see:
https://community.cisco.com/t5/wireless ... -p/4135411
I don't know if setting the Multicast helper to "full" on the wifi interface , will also convert this to unicasts!?
(Helper default setting is "default" , currently the same as "disabled")