2.4GHz stopped working on Linksys 1900ACS

Since about 12 hours now, the 2.4GHz connection on my Linksys 1900ACS stopped working.

For debugging, I set a previously unknown AP as the only AP on 2.4GHz, and it seems that clients don't see that AP when scanning (even though SSID broadcasting is on).

Clients that were previously connected to a known AP on 2.4GHz, do seem to get a partial connection. I found the following in my syslog:

Sun Jan 30 11:08:45 2022 daemon.info hostapd: wlan1-1: STA 4c:11:ae:04:0c:84 IEEE 802.11: authenticated
[...]
Sun Jan 30 11:09:13 2022 daemon.info hostapd: wlan1-1: STA 84:cc:a8:a6:8f:4a IEEE 802.11: authenticated
Sun Jan 30 11:09:39 2022 daemon.info hostapd: wlan1-1: STA 84:cc:a8:a6:8f:4a IEEE 802.11: authenticated

Where it seems that the clients attempt to reconnect, but don't continue to the associated state.

I do see the clients "show up" in LuCI under Associated Stations, however they do not seem to get an IP from dnsmasq.

I can still succesfully initiate a scan from the Wireless screen on the 2.4GHz radio, and this yields the expected list of wireless networks.

On one of the clients, the following log messages appeared:

wlp1s0: send auth to 00:25:9C:14:40:C5 (try 1/3)
wlp1s0: send auth to 00:25:9C:14:40:C5 (try 2/3)
wlp1s0: send auth to 00:25:9C:14:40:C5 (try 3/3)
wlp1s0: authentication with 00:25:9C:14:40:C5 timed out

I was on 19.07 when this issue occured the first time. I have since upgraded to 21.02, however this did not change the issue.

Is this a (partial) hardware failure? Or is maybe something else up?

Due to the change from swconfig to DSA in version 21.0.x, configurations are not upgradeable for the following targeted devices...

ath79 (only TP-Link TL-WR941ND)
bcm4908
gemini
kirkwood
mediatek (most boards)
mvebu
octeon
ramips (mt7621 subtarget only)
realtek

Your device is a mvebu

If you kept your configs when upgrading from 19.07.x, you'll need to re-configure from scratch.

I didn't keep my configs, I reconfigured it completely when migrating to 21.02. But the same problem still exists