Xbox One turns on for a few minutes, shuts down completley after.

Try a full shutdown.

Press and hold the power button on the Xbox until it shuts down.

Once the light on the power brick has turned orange you should disconnect the power for a few minutes.

After a few minutes plug back in, switch on and try again.

Hey there. I don't know if you've tried this, but in the past when my Xbox refused to communicate with my PC, a hard reset fixed it. To do this, go to Settings, Power, Turn Xbox off. Wait until it is fully shut down, and turn it back on and try again after
a few minutes. If that doesn't work, do the same thing, but unplug the power cord from the back of the console for 2 minutes after it is shut down and then try again.

I just set up my console a few minutes ago, and it also took a long time after the update downloaded waiting at the green Xbox One screen. I turned the console off by touching the power sensor on the console, and the console started to shut down with a pulsating
power light. After about a minute, the LED on the power brick turned yellow, when the console completely shut down. I then powered it up with the guide button on the contoller, and after a short wait on the Logo screen, setup continued.

Maybe it's really a case of "have you tried turning it off and on again?"

As soon as I try to turn it on it shuts down but I might try it in a few minutes

Hi, _

Thank you for posting in Microsoft Xbox Community. I understand that you are using one of your controllers to watch streaming apps and they automatically shut down after few minutes. This is a normal behavior of the controller to save battery where it automatically turns off after 15 minutes of inactivity. Can you further elaborate your issue when playing Fortnite?

Regards,

Alvaro