As your using a mesh system for WiFi, is it running in bridge mode so it gets IP addresses from you main router? Its likely that your not and are running unknown to yourself two separate subnets. Roon won’t see devices that are on a separate subnet. Check that your Roon core IP address is in the same range as one of your WiFi devices your not seeing in Roon, the first 3 numbers assigned should be the same. If not then that’s your issue and needs to be remedied. If not then checking firewall etc as previously posted would be wise.
Thanks, I will check that to be sure but it seems unlikely as I can access the three air play devices that are connected to the mesh via iTunes on the PC and can control them using remote. I assume the communication protocols would be similar for Roon and iTunes?
Look in Roon settings, audio.
Roon needs a flat network with all devices on the same broadcast address. This is not a prerequisite of others.
What IP addresses are your server and wireless end points on?