TV buffering

Server Version#: 4.108.0
Player Version#: 1.83.1.4061-d3f45728
Tuner Make/Model: HDHomerun Flex4K | Firmware 20231020
Guide/Lineup name: MacMiniNAS
Using XMLTV?: ?
Channel number/Name: all
<If providing server logs please do NOT turn on verbose logging, only debug logging should be enabled>

I have my Plex server setup on a 2014 Mac mini using both an NVMe drive. movies, music, and live TV plays great on iphones, tablets. I can watch TV using the HDHomeRun Mac app, but nothing with Plex player.
Whether I use the Plex player for Mac or a web browser, I get the buffering.

Any suggestions are much appreciated.

While playing with settings and reading forums like this, I reset the playback quality settings to maximum, and rebooted the server app. I also removed and reset the TV tuner (HDHomeRun Flex) and rebuilt the guide. I was able to view several channels for 3-5 minutes. Then, the buffering began.

My home network is a wifi mesh Eero 6+ with T-Mobile Home internet with download speeds of 100-225Mbps.

I am able to watch TV using the HDHomerun app. No buffering issues.

Any suggestions much appreciated.