I have had this problem recently despite having adequate broadband speeds - I have (hopefully) solved it by buying a netgear wifi extender, plugging it in next to the TV and running an ethernet cable directly into the TV from it - and have had a smooth, sharp picture ever since.
I use the NOWtv app on an LG set.
No idea whether that's a permanent solution or I'm just lucky - but for people struggling it's worth a go.
If it IS a solution then NOW should be sending everyone a voucher to buy one if it's necessary to run their service properly.
This is no solution.
I have wired connection direct to my TV and constant 40MB.
Netflix and Amazon both stream in 4k without issue. But Now TV can barely go 10 minutes without dropping to an image quality where you cant tell if you are looking at a human face or or a garden shed.
Now TV service is just plain abysmal, how you can charge people mo ey for it is beyond me!!
I have the same issue here, have tried all the troubleshooting on both a now tv box and my samsung tv, connect via wired connection wight an 80mb broadband service but constantly getting drops of stream quality from well over 4000 to just 90 seems the only way to get the quality back up is to stop the stream and reconnect absolutely useless watching live movies as by the time you put your pin in you lost a chuck of the action. I've now cancelled my movies pass and only have the entertainment pass becuase it was free from McDonnalds when thats finished I will not be a now tv customer anymore (yes Netflix and Amazon (4k streams) work great so I've come to the conclusion that the now tv automatic stream quality system works backwards and as this problem has been affection so many people from the start the only thing now tv do is up the price!
I get this on a Roku 1 box. After maybe an hour or so of good streaming the picture decays into an unviewable mess.
It takes about 5 minutes to reboot the thing back to watching: not good on live sports. It sometimes helps a bit.
I tried installing the Windows Store app, but then I'm into the "clever" (and utterly broken) 'intelligence' that Now TV attempts to do to count the number of simulatenous streams. The app tells me to stop the other stream. Stop the Roku, keep trying the app - it still complains.
This is not acceptable when watching live sports, Now. I don't care if you say "please try later" - that's not the point. You either need to fix the streaming quality issue or the stream counting issue. To have both is money grabbing laziness.
(There is NO problem for any other streaming service)