Check the box next to 'Allow all incoming connections.' MacFixIt reader Mike writes: Turn off firewall Open System Preferences, then click on the Security pane.
Try the solution above 'Just say 'OK'' again. Reset the Apple TV Reset the Apple TV by unplugging it from the power outlet, waiting about five seconds, then plugging it in again. This simple act may trigger a reappearance of the Apple TV in iTunes' device list. Just say 'OK' Navigate to the Apple TV tab iTunes preferences, and simply click the 'OK' button. Using a shotgun approach, however, most users can solve the problem, applying some combination of the following solutions: We've published a variety of fixes in recent weeks, none universal.
The issue can materialize randomly, or after updates to iTunes or the Apple TV software. A problem in which the Apple TV does not show up in iTunes' device list has proven particularly persistent and frustrating.