We bought a Onn Roku TV from Walmart around Christmas time and finally got to setting it up as an outdoors TV recently. During setup, it always says No Networks Found no matter how much we’ve reset the TV, certain TV settings, router, and changed router settings. We have even moved things around so the TV was directly next to the router and nothing, not even picking up a mobile hotspot as well. We have even tried an offline software update and nothing again.
Thanks for letting us know about the issue you're experiencing.
Have you tried contacting the TV manufacturer to inquire further? I'd suggest starting there to see what options or suggestions they can provide. Each Roku TV manufacturer provides direct support and warranty services for their products running the Roku OS.