I lost my ability to connect to AppleTV Airplay but then happened to switch off of 5Ghz wifi connection to regular (2ghz?) Wifi connection and it came back. My Apple TV is on the 5GHz network so I don't understand :-/
MacBook Pro 15", macOS 10.13
The AppleTV is merely set to receive 5Ghz and 2.4 Ghz. Your WiFi router has to be distributing 5 Ghz network for it to see it, and be within range. Check the AppleTV is in fact in range by seeing if you can put a 5 Ghz computer or tablet or phone on WiFi and see if the network is visible adjacent to the AppleTV. If it is, you may need to reset the AppleTV. If it isn't after that's the case, you may have a damaged WiFi antenna in the AppleTV.
Airplay not working on 5Ghz Wifi network?
