Apple TV shuts off

What is your model Apple TV? Identify your Apple TV model - Apple Support

Is it streaming anything when this happens? If so, from which content provider?

What is the current setting for the idle timer sleep? Settings﹥General﹥Sleep After﹥

The idle timer shouldn’t kick in when streaming video from any service, because the Apple TV isn’t idle then.

Unless someone else chimes in with a good idea, I would suggest to contact an expert from the Apple Support staff for further assistance. Contact Apple for support and service (phone numbers) or start your support request online (chat/​email/​callback).