Apple TV flickers and does not respond.

A little more information would be helpful. Do you mean the light flickers who you use the remote but it doesn't do anything. If so...

Your Apple TV may have become paired with another remote. Hold the remote close to and pointed at the Apple TV, hold down the menu and Rewind buttons together for 6 seconds or until you see a broken chain icon on screen.

I had this problem too...and I fixed it by unplugging the HDMI and replugging it into the ATV4. No more flickering on the TV. I hope this solves it for you.