My Roon Core is my iMac running (OSX 10.13.6); my main room listening is via an Onkyo PR-Rz5100 AV preamp. Roon only shows AirPlay or Chromecastr connections, either of which works as expected. How can I make the Roon Core use wired Ethernet instead? (The Ethernet connection works fine from other SW servers running on the iMac.)