Just to confirm, do you have an Realtek drivers installed on the Core machine? Realtek drivers have been known to cause issues with Roon in the past, please see this thread:
I would also double check that Roon is not by any chance being blocked by Antivirus or Firewall, I have also seen similar symptoms when McAFee/Kaspersky/ESET32 was blocking Roon/RAATServer from working properly.
Can you take a look and let me know if this helps?