We're excited to announce that we've fully migrated the Xbox Forums to their new home, here on the Microsoft Community forums!
As of today, going to forums.xbox.com will redirect you here to the Xbox area of the Community forums. We've moved all of your existing threads over so you can continue and start conversations with the new forums experience.
We sincerely appreciate the feedback you have provided over this transition and can't wait for you to check out the new Xbox Forums!
The media remote is not currently compatible with every app. As stated on its official support page, not every 3rd party app currently supports it. It sounds like YouTube is one of them. You'll have to wait on an update to the YouTube app to support remote