UI Buttons on xbox UWP not selecting first selected

Hi

I'm developing a UPW game that I want to deploy to a XBOX One. It has been a long endeavor to get the xbox to run the game, but everything seems to work now except for interaction with UI Buttons. I have configured the “First Selected” on my EventSystem to be a button on the UI that is displayed as soon as the game starts. This works well if I run the game locally as UWP running on Windows 10 with xbox one controller connected via USB, but it does not work when i deploy the game to the xbox (no button is selected when i start the game, so its not possible to start the game).

This is my first unity game and my first UWP application, so I’m probably doing something wrong - I just don't know how to debug this issue.

Anyone experienced anything like this?

Thanks Thomas