I would update the firmware for your TV. In order to do that though you need an internet connection. Wireless isn't working so you need to use the ethernet port on your TV. 2 ways to do that.
1. Move theTV closer to the wifi router and plug into one of those ports.
2. If it's not practical to move the TV, I'd get a wifi range extender (something like this one: https://www.amazon.com/NETGEAR-Version-Wi-Fi-Extender-WN3000RP/dp/B004YAYM06) with an ethernet port and plug the TV into that to get a wired connection.
Hopefully, the wired connection works. Update the firmware. Maybe that fixes your wireless issues. If it doesn't but ends up working with the wired connection, then continue with the range extender.
