Using macOS Sierra 10.12.5, iMac 27-inch Mid 2011, AppleTV Model A1469 7.2.2 (8015) Connected via WiFi
I have an Apple TV that used to work, however, now whenever I mirror or extend my display from my iMac it only shows a blank/black screen with audio.
I found this post, Apple TV Black screen (OS X Yosemite ) however, the solutions there did not work for me, and I am not sure how it worked for the OP.
I also found How to Fix an Apple TV with a Blank Screen and reset my Apple TV to factory settings, but still the same problem persists.
The audio works fine and I can switch between internal speakers and the AppleTV but there's no video on the AppleTV.
Any ideas at all are greatly appreciated...