Edit: I don't know if it matters, but I started a movie that was already mid way through. I would assume that starting a new one from scratch works just as well, but did not try this.
Yup, and if it still errors, go into settings, fine the nervous settings and have it reset. That has always fixed issues for me in the past with that app.
To get surround sound from Netflix on Apple TV (or any other device) at least in Sweden you have to change an video quality setting on your Netflix account page: https://movies.netflix.com/HdToggle
When it's set on "High" it only streams with stereo sound. But set on "Highest" I finally get surround sound on my Apple TV.
And yes, trying to figure this out drove me crazy changing all kinds of settings on my Apple TV, surround system and television set. And no, Netflix support didn't figure this one out for me, it was more of a coincidence 🙂