The problem may be with Windows 10. If you've already tried all the solutions proposed by Netflix support over the phone or email but nothing worked, there's another possibility that should be checked before anything else - your operating system version. As of May 2018, only Microsoft Edge still had an issue with Netflix playback via soundbar under Windows 10. Although it has been resolved in the preview version of Windows 10 upgrade, it could still be a good idea to use either Firefox or Chrome instead for now if you encounter this problem.