There's every chance that your phone is dropping the WiFi connection and reverting to your mobile data connection, then picking up the WiFi again, then dropping and repeating the process....
What happens if you turn the data off?
Then move about 1 metre away from your router?
I have resolved this promblem, it was not the connection as stated I have 4g and a solid WiFi Connection. Anyone else who hs this problem needs to DL nowtv Beta from google play.........login as normal and you can also watch the other Sky tv Channels :-) Ps the beta Logo is black instead of blue..........
Here is the link, of course it would have been far better if the normal app updated as most do!!!!
See my post below, DL now tv beta from play store should fix this problem