Lose connection to wired devices from Panoramic WiFi extender

I have COX panoramic WiFi with two extenders for my upstairs and my basement.  Off my primary cox panoramic WiFi modem I have a gigabit switch and hardwire connections to a server, NAS, and two printers.  

My problem is that when I’m connected to my upstairs extender, I routinely lose connection to my LAN devices hardwired off the main modem.  Off the extender I still have WiFi and internet connection through the modem, however.  If I unplug and reset the extender, and connect to the extender WiFi, the hardwired connections are restored.  If instead I move and connect to the WiFi on the primary modem, I am also able to connect to my hardwired LAN devices

I’ve also found the admin interface to the Arris modem/WiFi router (sorry to be blunt) is **.  It routinely times out and locks up making it extremely difficult to check the settings.  There also doesn’t appear to be a way to check the individual extenders.