Audio playback only on USB headset, not system speakers PrEl2019

When using a USB headset, I can hear the audio track(s) just fine.  But when headset is removed from USB port, playback appears to be muted when editing my videos using PremElem 2019.  System sounds, iTunes, original video clips...they all sound great through my standard system audio, as usual.  Only PremElem audio is silent.

Have restarted system, restarted PrEl software, no luck.

Thanks for your advice.

- Mike Mc-

PremElem2019

Windows 10