Multicast addresses for Spotify Connect, Youtube Cast Recevier

Volumio 3.198 on Raspberry Pi 4

Plugins:

  • Volumio Spotify Connect2 (3.0.8)
  • YouTube Cast Receiver (0.1.2)

WiFi A has my Pi with Volumio, a Chromecast and my Receiver with Spotify Connect in it.
WiFi B has my phone and PC in it.
I have set up Multicast policies to alllow mDNS and SSDP traffic between both networks.

I can access the volumio.local web interface while connected to WiFi B from my PC, and the Volumio app on my phone can find the Raspberry Pi, so mDNS seems to be working.
The Chromecast and Receiver’s Spotify Connect show up as well.

However, Volumio does not show up on the YouTube or Spotify App when my phone is connected to WiFi B. But as soon as I switch it to WiFi A, they show up.

Is there anything here I can do to make it work between WiFis?
Do these plugins use different multicast addresses?

Thanks for your help!