I was also having issues with Netflix app.. I was however able to watch Netflix through the edge browser.
I dug a little deeper and reinstalled Silverlight because the Netflix app is designed to use Silverlight. I did get a better response from the Netflix app at this point, but it still would not play. It would get to a 21% on the buffering gui and hangup every time. I continued to try to and find a solution to the problem and came across this:
Media Feature Pack for N and KN versions of Windows 10 KB3010081
I installed this media feature pack which contains the windows media player. this pack also contained the codecs needed to play certain videos on your system and it has also fixed my Netflix app. I do not know if this will work in your situation but it has fixed my streaming video problems.