R320 AP - WEBUI not loading - 503 service unavailable

[Dirtbike]

Hi All,

I have bought a used R320 AP running 6.2.3.103.238 which is intended to added to an existing Unleashed network and to keep costs down for a client who already has a further 11 R320 AP's and 1 R510 (from memory) running as unleased access points and the 5 series being the master AP.

The issue I have is that the AP will not load the web interface, 503 Service unavailable. I found an old reddit sub that stated that this could be by design if they were managed by an older director etc...

Within our office network and not on the client site I have tried the following steps to gain access:

1. Reset the AP using reset pin in the back - WEBUI still unavailable after it boots back up.

2. Reset AP again and can SSH into the unit with the default credentials, however the AP seems to reboot after approximately 5 mins.

3. The AP then appears to boot up as though configured e.g. the 2.4G & 5G lights are illuminated on the AP and I can see additional traffic on our firewall. These are the IP's the AP calls back to once it goes into this mode, prior to that it's just google entries listed for NTP:

34.89.230.65 - 65.230.89.34.bc.googleusercontent.com
172.64.149.23 - no reverse pointer
192.124.249.22 - cloudproxy10022.sucuri.net
34.170.110.156 - 156.110.170.34.bc.googleusercontent.com
95.101.251.61 - a95-101-251-61.deploy.static.akamaitechnologies.com
142.250.187.219 - lhr25s33-in-f27.1e100.net

It's almost as though I can break the boot up routine if I SSH after the initial reset but have a limited time before I guess it phones home to the controller it was previously configured by (if I stop it from getting external access it doesn't reboot and deploy the configuration).

I would assume there is someway of updating the firmware to place it standalone mode or enable the webui?
I don't think taking it to the client site will work as the Master AP will not see it with mismatched firmware (I don't think this firmware is even the unleashed variant).

Any suggestions or should I just return it to the seller?