I can only say what worked for me and I really hope that someone finds this in the comments or a reply because I didn’t know how to comment in here and I’m sorry I have been on the phone all day with on Ryukyu hotline they sent me all around the world but when I finally got to the person, this is what they told me to do and it worked my Internet would not connect at all. It was not the Internet. It was the TV MAC address which is an hardware faulty, is what I was told. I tried everything in the comments nothing worked, so I finally had to bite the bullet and call Roku hotline. I’ll unplugged the tv then I press the power button on the TV actually for 60 seconds, then plug the TV back up and go to your Wi-Fi connection and it should work it did for me to save time from calling the hotline and being on it all day, and if you’re like me, who restarted your whole system it let me put my apps back on through my phone instead of individually doing it on tv I have a ONN ROKU TV 50” I hope this helps someone
My Roku Ultra hadn't updated firmware in over a year. With the assistance from a Roku support rep, I solved my issue with wireless connectivity by plugging an Ethernet cable from my network switch into my Roku Ultra and it immediately performed a firmware upgrade to the latest version. After the Ultra rebooted, I disconnected the Ethernet cable and successfully connected to my WiFi network and haven't had any issues since.
Roku Ultra (4660, 4661, 4662 series)
