I have two Wi-Fi networks, VPN, and not-VPN. They are physically parallel and identical, a pair of Decos side by side in each location.

The problem is one of the Decos on the VPN network has frequent connectivity issues. The non-VPN Deco right beside it has no issues whatsoever.

When it won't connect, all the usual stuff, rebooting, power-cycling, running the network optimization utility, doesn't seem to make much difference; at some point, it will reconnect, and then work fine for the next few hours, few days...who knows?

I tried swapping it with another Deco from another location. The problem stayed with the location.

I tried isolating one network to 2.4 GHz and one to 5 Ghz. Both ways. That made no difference.

I tried moving the Deco to other locations in the same area-no change.

I tried rebuilding the entire VPN network. Reset and re-configured every Deco. Problem remains.

I tried running the network interference scan and testing signal strength. Interference is "low" and the signal is 100% -30dbm

Any ideas? Keep in mind there is a Deco that sits right beside the problem Deco and has no problem at all.