1. Samsung HDTVs are notorious for distance issues. Must be 20 or less feet to router/hot spot.
2. Try changing the DNS to 8.8.8.8

Also, Samsung services sometimes go offline. Call 1800SAMSUNG to ask if they are up or off line. Be aware they can be pedantic about this. Samsung uses a cloud service that means it has never has a server down issue. But for us, that's down none the less.