If you didn't change the router, nor any settings in it, and all your devices (tablets, phones, laptops) work with WiFi, but your TV does not, it seems more a TV issue than a router/modem issue.
What happens if you hook your old modem up again (just as an experiment)?
Before calling (and paying for) a tech, I'd see if any of your friends or nearby family have another router to try. If that works correctly, there's a good chance that any router will do. A new router is cheaper than a visit of a tech, be it from the router company or from Samsung.
I hooked my new modem up. All my devices are logging on to my wifi with no problem. The only issue i am having is the apps on my samsung smart tv will not work. My tv is saying i have internet and i have been on the phone with customer support for hours. I called my Internet provider and there is no problem with the modem because when i plug my tv into the modem with a wire, the apps work but then i have to unplug my router and i get no wifi. So the problem appears to be my router, i was told by time warner cable that my router needs to be configured. I have a d-link router that was supplied by the cable company years ago and we pay a monthly fee for the modem. I was given a phone number for the router company but i have to pay to get support. The cable company made me upgrade modems cuz they said the old one would not work when the Internet upgrades. Why are all my devices working with my router except my smart tv apps and will reconfiguring my router to the new modem fix my problem? I'm running out of answers, i really just need a tech to come out here. HELP PLEASE!!!