Q: In playing a movie the audio continues but the movie part stops and starts. Is this a buffering problem

In playing a movie from Pureflix the audio continues but the movie part stops and starts. Is this a buffering problem & how fix. I am on a Safari wifi using airplay with my Iphone6.(IOS 9)  Though I have Pureflix app on my Iphone, I am unable to see the Pureflix Icon on my Mirrored HD TV screen.  (2nd issue).  First issue is the movie stopping and starting.  Apple TV worked yesterday, but today lack of synchronization for some reason.  I have up to January 15th to decide whether I want to keep Apple TV purchased through Best Buy.