I have two ATV's in my office, an atv1 and an atv2, with different names. I use them to do interactive presentations with clients and they've generally worked fine. I recently found I can no longer use airplay from my mac on either one. Airplay from my iphone works fine. I'm using a macbook air with High Sierra v. 10.13.3. I've checked my firewall settings. Block all incoming connections is not checked, automatically allow built in software and automatically allow signed software are both checked. All are on the same network and signed into icloud. Any ideas or suggestions?