LMS plugin with DAC +ADC

I am trying to use the analogue in on my DAC +ACD to stream analogue source to other devices. I have 3 devices, all raspberry pi’s with. The one with the ADC has LMS on it and the 2 others have squeezebox. I followed this guide in order to set it all up:

I am able to log into LMS on the ADC device and I can select ‘Volumio’ as the squeezebox device. I can send streams from the server device to the other devices, for e.g. a web radio stream, but I cant send audio from the analogue source. I made a favourite and named it ‘analogue’ and set the URL to “wavin:defualt” as per the tutorial, however it doesn’t work. When I click play, it counts up from 0:00 to 0:03 and then goes back to 0:00 without any audio being heard on the receiver device.

I would really like to get this set up if anyone knows what might be stopping it from working.