Smart TV pop-up bug. Still there is no solution for this. Just disable WiFi or internet connection. I had the same issue. I did it like this. Connect WiFi when you need only. Or do not close your mobile to TV. Because it costs issue because of Facebook.
@Rihad: Does the notification continue to pop up if you select 'Deny'? I'm not sure if this is applicable, however if you have a Samsung device with SmartThings, open up the SmartThings app > Tap the 3 lines in the top left > Tap the cog in the top right of the pop up window > Tap View, Tap Sound, and toggle this off if applicable.