I have a Samsung Model UN55MU6300F Smart TV and have the digital (optical) audio output connected to my Pioneer receiver using a digital to analog converter. When playing shows from TV cable, TV cable recordings, or audio from the flash card reader port or audio from my laptop using Serviio, the output to my receiver and external speakers works fine. However, when I play movies from my laptop using Serviio, there is no external audio, only from the TV speakers. The same thing happens using any of the smart TV apps, like Netflix, Prime Video, YouTube, etc. When I mute the TV speakers, I still get the beeps from my external speakers going from app to app and the "ta-da" when loading Netflix, but no external audio after that. What is the problem?