Try 126.96.36.199 next time.
Samsung usually goes over resets, firmware and the DNS. Be sure the date and time are set in the TV to your local time.
I recently purchased a samsung 55" 4K tv, model UN55JU6500FXZA. I did have ATT U-Verse and I was able to connect and use the apps just fine. I switched to RCN for faster internet and the smart hub will not work with it. My computer/phone/xbox connects to the internet and works; but not Smarthub. I've tried the Wifi and hard-wired in and neither work. It says it's connected to the internet, but no apps will load. If I switch back to U-Verse wifi, the smarthub works fine again. Neither RCN or Samsung customer service was able to help; any suggestions? Thank you.