1. Set the TV to output over the optical and test that works with OTA (over the air) and other sources.

2. Repeat the steps at https://help.netflix.com/en/node/14163
3. Be sure you have a TV optical port as noted at https://techguyeric.com/2013/07/14/how-to-run-audio-from-your-smart-tv-back-to-your-av-receiver/

4. Some apps don't have surround like most of YouTube.
5. http://www.tomsguide.com/answers/id-2891745/samsung-smarttv-netflix-app-soundbar-issue.html notes 5, 5.1 and PCM.

6. In some version Netflix I have to select the 5.1 audio track.