I can't find YouTubeTV available with a streaming stick. I have no problems with 3 tv's using Roku Express.
Just to confirm things. your Roku Streaming Stick is on the same Roku account as the three Roku Express devices? Settings > System > About
You have YouTube TV working on those Roku Express devices?
DBDukes
Roku Community Streaming Expert
Note: I am not a Roku employee.
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It would also help to know the model number of the stick displayed under Settings->System->About.
Only 1 Roku account. Settings/System/About shows "Express" and my e-mail address on Roku Express and "Roku Device" plus my e-mail address on streaming stick which is purple but shows no model number. Problem is that Roku (streaming stick) shows no YouTubeTV app available when searching. Express shows the app and sets up in the usual manner.
[Removed by author. See following post by @Tivoburkee ]
DBDukes
Roku Community Streaming Expert
Note: I am not a Roku employee.
If this post solves your problem please help others find this answer and click "Accept as Solution."
Mentions in last post its purple stick, that's either 3400 or 3500 stick. Neither is compatible with you tube tv. You have access to youtube tv from the regular youtube app, and you can even sign in to yttv, but if try to play a selection you end back at the home screen. It just doesn't work on that old roku.