core: Google Cast Integration not detecting Cast Devices

The problem

Google Cast devices not detected by HA when adding cast integration

Environment

Host OS Windows 10

HA Virtual Machine - - VirtualBox Operating System HassOS 4.17 HA Version 118.3

https://www.home-assistant.io/integrations/cast/

Problem-relevant configuration.yaml

None - Adding integration though UI.

Traceback/Error logs

No errors in Supervisor or Core logs shown for Cast. I do see one for supervisor.api.ingress, unknown if it has a part to play in the issue. 20-11-25 20:08:34 WARNING (MainThread) [supervisor.api.ingress] No valid ingress session None

Additional information

Home Assistant Virtual Machine and Google devices all on the same IoT Vlan. Google cast integration can’t find the google devices, half dozen of them some minis, a hub, and a few CC Audios.

WIn 10 PC hosting the VM is dual networked to both the Iot Vlan and the Trusted Vlan. HA VM is bridged through the IoT Vlan network link, and it has its own IP on the Vlan.

My phone, Laptop, and PCs, on the trusted network can see and interact with the casts which are in the IoT VLAN

So mDNS on my ubiquity gear is working, IGMP snooping on the IoT VLAN is now disabled. it was enabled. no change either way.

I have not attempted manually adding them as of yet.