Apple TV Sleeps

I have two Apple TVs 3rd Generations; one in the living room and one in the bedroo.. Both of them have the latest firmware updates, however, the one in the living room will not wake up when I am using the remote app. In fact, it doesn't appear in the remote app at all until I turn it on using the Apple TV remote. Then it will appear on the app. I have carefully compared the settings on both ATVs, and they are the same. However, the living room ATV does not appear on the remot app until I wake it using the remote. What am I missing?

BMG