Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
I'm on hold with Apple support right now. I'm thinking either Roku OS 9.2 (I'm running 9.1) is required, my version of Roku hardware or HD TV vs 4K TV. I even tried to DMZ Host the Roku to rule out any firewall issue. As I mentioned I have two (2) identical Roku Ultras with same issue.
Roku OS 9.2 is NOT required for the Apple TV app. Roku OS 9.1 build 4919 is the minimum requirement (For Roku Players and Streaming Sticks).
Have you tried logging in with a separate Apple ID account (maybe one without 2-factor authentication enabled) to see if this is successful? That may help eliminate some of the possibilities of the root cause of the issue.
Can I jump in and ask ...I've set up a Apple account on my tablet but when I try to sign in on my Roku stick plus ....it tells me I need a ITunes account. I don't have a computer at all ...so how do I get this to work . I've already had to jump thought hoops to get this far