apple tv 3rd generation A1469 activation failed

Apple TV 3rd gen model A1469 works fine as far as playing all my content including movies I've purchased, but the problem is when trying to use AirPlay or Screen Mirroring on my iPhone the apple tv doesn't show up. Yes it's on, yes they are on the same WiFi, yes they are both up-to-date.

The only issue seems to be is that even though I'm logged in and using it just fine, when I go to settings general about it says at the bottom "activation failed"

I've done a restart and a restore and no change.

Does anyone know how to "reboot" this thing to try and start from scratch?