Restore Apple TV
If Apple TV still doesn’t respond after restarting, try restoring it. When you restore Apple TV, all data is erased.
Restore Apple TV. Do the following:
In Settings , go to System > Reset, then select Restore. Restoring Apple TV can take some time, so be patient.
If Apple TV still doesn’t respond, disconnect the power and HDMI cables from Apple TV. Connect one end of a USB-C cable (sold separately) to Apple TV and the other end to your computer. Open iTunes on your computer, select Apple TV in the Source list, then select Restore.
Comprehensive support information is also available online at www.apple.com/support/appletv.