TuneIn Radio Issue

I have a raspberry pi the very first one that came out and I have Volumio installed with some plugins and I am having an issue with TubeIn Radio. I want the radio to play constantly and my issue is it will just stop working. It seems that the volume goes away after an hour or so of music playing but when I log on to the web interface it shows that the radio station is still playing but no sound comes out. To get it working again I have to stop and start the stream. I am using the Aux out to an FM transmitter and the radio station I am playing is HPR1 Traditional Country music. It does seem it’s just TuneIn that does this because I played Pandora Radio and it never did that. Is there anything I can do to fix this? My father loves his old country and I got him to get rid of Sirius XM and he is kind of getting mad his radio is not up most of the time.

Does anyone have any info? I have used it for days straight when using HDMI out it never stopped like it has with the AUX output.

Trying an USB external DAC that I had lying around will post back results.

The external USB DAC did not help. I think I am going to get an HDMI to AUX DAC. Just like when I said I had it hooked up to HDMI to my receiver when testing it out I never had an issue it played for 3 days straight no problem. Will report back once I get it.