The EXN100 cannot decode Dolby or Surround signals, so you will need to adjust your TV's audio settings to PCM or Stereo to achieve audio.
If you've done this and still experience no audio or audio glitches with apps such as Netflix and Amazon Prime, it's likely that these apps are outputting a Dolby or Surround signal.
If this is the case, you'll need to change the audio settings within the apps themselves to PCM or Stereo.