AppleTV 4K can't find server

Channels Apple TV Troubleshooting
#1

After working great for months, my AppleTV 4K suddenly now can't find the Channels-DVR server. Channels-DVR is running on a Debian server.

Checked all the basics: IP address, port #, network connection, restarted everything. Other devices, PC, Mac, Ipad and Iphone all still work fine.

Suggestions?

#2

IF the Apple TV 4k has a wired ethernet connection, unplug it, and try using it via WiFi for a test. See if that works. It'll grab a different IP address.