So you have unplugged the Apple TV from power for a few minutes and restarted the computer?
I didn't unplug the Apple TV, but I did restart the computer.
Also I have the same problem with another mac
I will try unplugging the Apple TV and get back to you
OK then do that unplug the Apple TV from power to shut it off there is no on / off switch. Then plug it back in and try again. It sometime needs restarting like a computer
That did it. Thanks.