Hi @Anonymous User
I don't own a Samsung Smart TV, but have you tried some of these basic suggestions below.
Exit the NowTV App and temporary unplug the power to the TV for about a minute, together with a reboot on your Router.
Let the Router reboot first and give it about 5 minutes to settle down, then restart your television and see if anything plays on the inbuilt NowTV App.
If that doesn't work maybe try deleting the NowTV App and re install the App again.
