Room Controls: "Public IP is forbidden"

We're setting up a new room where the projector should be turned on or off from the touch panel, but if the device profile uses a public IP (i.e.: not a RFC1918 one) after a few seconds the error "Public IP is forbidden" appears. This does not happen in a similar setup in a different university (same company and hardware).

What could be causing this? Our Zoom "super admin" says there are no options allowing or forbidding public IPs for Room Devices. Are there special firewall rules to use (external to internal; we have no restriction on that LAN for outgoing connections)?

Thanks for your help.

Luca Polo - University of Padua - Italy