Apple TV on Ethernet; Apps cannot see network

My Apple TV 4th Gen (A1625; tvOS 18.0) operates fine when connected to WiFi. I connected the Apple TV to my WiFi router (Arris NVG589) via an ethernet cable (new 7-ft cat6) hoping to stop or lessen the drop outs, long load times, buffering issues, etc.

The homepage shows an icon indicating WiFi is disconnected.

Settings:Network displays Ethernet: Connected and seemingly valid IP and ethernet address. But opening any app on the ATV displays a message “Not connected to network” or something similar.

The Settings app displays a blank screen after selecting functions that require internet access (“Update Software”, “Start Diagnostics with Apple”).

I did both hard and soft restarts to both devices (twice). No change.

Tested the ethernet cable on my laptop; it works.

Television is a twelve year old Samsung “dumb” TV. Just a monitor with a tuner and some HDMI ports. I’m hoping for some magic spell from the community before I reset the Apple TV. I doubt that will fix the problem and it’s a pain in the patooty:)

Suggestions?

Thanks.