Hi @Michael_Poon. Thanks for your patience. we need some details on your setup to help us move forward.
Please provide a brief description of your current setup using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so we can have a clear understanding of how your devices are communicating.
One other thing you can try in the meantime is to uninstall Roon from your Core devices, go to our downloads page, and download a fresh version of Roon directly from there. Once you install the fresh versions, try running Roon and let us know what happens.