Help is urgently required.
Help is urgently required.
Consider engaging a local company for networking challenges like these. Solving issues at this level needs someone with on-site expertise. If you're nearby, contact Crosstalk Solutions, Lawrence Systems or Willie Howe. Additionally, examine firewall settings that could be restricting LAN traffic. For example, if certain Apple TVs aren't working, they might belong to a specific restricted VLAN, preventing clients from other VLANs from connecting.
This appears to be the probable reason. With Wi-Fi improvements, the wireless networks are likely separated from the physical network. It seems there could be distinct networks such as 'guest', 'student', 'staff', and 'internal', each controlling access to the local system. You might reach out to the installation team for details on configuration or confirmation about which network your device should join so it can communicate with the AppleTV.