I'm trying to debug an installation running airupnp (ARM version, on a Raspberry Pi) where all the Sonos devices are being correctly discovered, and the RAOP advertisements are being correctly sent, but the AirPlay targets are not appearing on Apple devices on the same network.

Other (native) AirPlay devices are appearing on the Apple devices, and the airupnp ones did also appear temporarily on one occasion. The Apple devices are connected on WiFi ... I'm awaiting the results of a test with a wired device. The obvious hypothesis is that this isn't an AirConnect issue, but that something in the network infrastructure is impeding the RAOP advertisements.

So ... I'm looking for any suggestions folks might have about what to investigate, what troubleshooting steps I should try, etc. This is a remote installation, so I have access to the Raspberry Pi but not to anything else on the network.

Thanks for any suggestions!