Apple TV has Ethernet connection, server is Qnap 241+
Tested the router configuration by removing everything except internet connect the server and the Apple TV including turning off the Wi-Fi and increasing router priority for Apple TV and server with not effect on the problem. I think that eliminated the router as the source of the problem. The Apple TV still streams several other sources the the tv with out any problems so I eliminated that as a probable error source.
Solution….
Tried connecting Apple TV directly to the server but that just gave me numerous errors so backed up one step and tried Apple TV to the router to the server and then restarted the Apple TV and server. This is the mobile configuration I have used in my trailer in the past(no internet). My setting in Plex is with no streaming services. When I accessed the server through the Wi-Fi everything looked normal, accessed Plex direct on the server and it worked with the expected lack of a TV guide for the dvr. Tested the Apple TV and it is now working. Reconnect the internet and refreshed the TV guide.
So what was the problem , I can only speculate that at some point something in Plex was looking for a response during video loading that it could not get probably from a internet connection. I have had a couple of the free steaming services turned on in the past but do not use them. Off for now.