Samsung does it different
Try the usual such as the Google DNS entries (noted in the CNET Networking forum top post) and be sure the router and TV date time is correct.
After that it's up to you to decide if Samsung's system is too different to keep. We know that they require you to sign into Smarthub and if there is any glitch on their end (has happened many times) then the house of cards falls down.
I wish they would learn from experience but it appears their leadership is intent on other goals. Robustness appears to take a back seat to their other goals.