I found the diag log . The info for the denonav is
Playback Devices
UPNP:33419d06-8dc3-1c06-0080-0005cdda9256 => {DeviceType=upnp-avtransport, DisplayName=Denon AVR-X1500H} IP=null (selected=true)
Player=UpnpPlayback
So I assume the UPNP portion is part of the 'url' I need to add ?