So I have 4 Roku in my house. I'm only having an issue with 1--we're connected to the internet (checked internet connection on Roku). I've reset the system. I've unplugged it & then plugged it back in. You can click on any channel (YouTube, Prime, etc) and nothing loads. Eventually a message says to check the internet connection. Anyone else experienced this? This Roku is only 2 yrs old.
How is your ISP? Recently Comcast/Xfinity and Cox updates have caused problems, but since you have 3 out of 4 Rokus working without issue it doesn't seem likely that that's the problem, but you never know.
I have 4 Roku Ultras and use Xfinity for Internet. The newer model (4800X) will not play Xfinity Stream app and has issues playing back Amazon Prime, Disney+ and Netflix. The older model can play Xfinity Stream but has buffering issues. These issues started 2 weeks before my units updated to 10.5.
Amazon Prime, Disney+ and Netflix work on 3 different TVs without issue.