No problem using my NOW Hub Router with my Hisense Smart TV over wifi here.
First thing i would try is press and hold in the reset button on the back of the NOW Router for around 15 seconds and start the setup again on the Hisense TV (give it 5 minutes for your Router to settle back down).
Also double check the WiFi password where O and zero can be confusing.
If that doesn't work go into your NOW Router webpage settings and try using a different wifi password from the one that came with your Router.
I would also recommend splitting the two wifi networks on the NOW Hub 2.
Got a NOW Broadband Hub Two? Splitting the bands on your Hub to create 2 different Wi-Fi networks can help to improve the speed to your devices. Here’s how to do it:
Keep in mindYou need a NOW Broadband Hub Two to split your Wi-Fi bands. You can't do this with the older-style NOW Hub.