New XG Locks up Every 21 min

We are installing a new XG 430. We have has a Sophos partner port all our rules over from our SG UTM. 

We made the cutover and all seemed fine, so we thought while we had the downtime we would update the XG to the latest version (18.0.4 MR-4).

After some more testing, the XG suddenly locked up and seemed unresponsive. No internet, no web GUI, although the front panel seemed to still work.

After a reboot it was fine again, until it wasn't. another reboot and then lock up. Each lock up showed 21 minutes on the uptime on the front of the XG.

Reported to Sophos, who came back to me with a promise that they know this issue and the fix is to reinstall the OS from a usb stick. So I took a backup, did the re-install, reloaded the backup, swapped over again, and again it locked up.

Strange thing is that it had been sat waiting for us to switch back again for 5 days, but 20 minutes after we plugged it in to the network was when it locked up.

I'm at the point of having called Sophos twice last night to report back and look for a solution, and both times being hung up on. This morning I didn't even get through to a person before being cut off and our account manager is on holiday until next week.

Anybody any ideas of where to start looking? I feel like it must be some kind of timeout setting as its always the same amount of time, but I haven't seen any setting equating to 21 min anywhere. 

Thanks for any feedback



Edited TAGs
[edited by: emmosophos at 7:39 PM (GMT -7) on 14 Apr 2021]