Loss of audio output on Rasp 2 w/ Spotify

After about a day of playing continuously I lose the audio output. I check the UI and it says that it’s still playing. Behaves normally but I’m not getting any audio. Even after rebooting it wouldn’t work. I took it home (from the business) and tried again and it started working again. Any idea what might be happening here? Is it possible that it’s getting hot after a day of use? Wouldn’t it overheat faster and give me trouble sooner than a near full twenty four hours or so? I have no heat-sinks or cooling, would such be required for running Volumio? What else might be the culprit?
The problem is limited to Spotify. Web radio stations output audio while Spotify does not. Anyone else have this issue?