ATP500 & WAC Points Dropping - reason 2 may be the cause?

Hi All,

We are running an ATP500 in our office with 2 x WAC6303D-S access points.

At random times throughout the day we get no internet over the WiFi and it seems that devices cannot obtain an IP address (even though they've been previously connected a few minutes previously).

When looking on the "station info" page on the firewall I see that many devices have a 0.0.0.0 IP, and the channel is listed as 0.

The only way to get the devices back online is to reboot the AP's and the devices then reconnect.

Logs are pretty sparse, however I can see multiple of the below logs showing for different devices.

STA: MAC ADDRESS OF DEVICE has blocked by prev-Auth Failed on Channel: 44, SSID: XXXXX , 5GHz. reason 2, Interface: wlan-2-1.

Not sure if this is related or not, as it seems all devices disconnect at the same time. Including Sonos music players etc.

We are on the latest ATP firmware, and WAPs are updated also.

The latest change that we've made is to change authentication from WPA2-Mix to just standard WPA2. Connection has been stable since making this change, but something is clearly wrong for the above logs to show continuously.

I'm at a loss as to what to check now so would love to hear some input from those who might have had a similar issue!

Thanks!