To everybody having this problem with your Roku device:
Are you able to view any content on https://therokuchannel.roku.com/ from your desktop, laptop, tablet, or phone when they are connected to the same network as your Roku device?
If you're having the same problem as we have, you should be getting a "Something went wrong. Sorry, this page can't be viewed. Check your browser settings and try again." error screen.
PS Before anyone asks, we already tried rebooting our router and trying a different DNS. All of the Roku channel's competitors play on all of our Roku and non-Roku devices without having to change any of our router or isp settings. So, at least in my case, this issue has nothing to do with Roku hardware.
PPS When connecting to https://therokuchannel.roku.com/ on our desktop while using a VPN and choosing any US server, the problem goes away and we are able to watch any content as usual.