Try the advice on this thread:
I am having the same problem and again it isn't my connection speed. It worked fine before I was forced to download this new player, i am very frusrated. If you post the answer people can read it rather than having to message for this secret PM you are sending people. Please can you tell me how to fix this issue?
My Now TV player is really awful. When I try to play it on my laptop, the program loads super quick and there are no buffering issues, but the audio skips, jumps and repeats itself all the time, which is really frustrating and I can't watch any shows at all.
There is nothing wrong with my internet speed (just checked), and I've tried connecting it via cable. Netflix etc work absolutely fine, so I think it is a problem with the app.
Can you please advise me as to what to do next? I'm paying for an entertainment pass so it would be great to actually watch the shows! (hopefully this is sorted before game of thrones comes out on monday )