Thanks for contacting support regarding this issue. Can I please ask you to verify that the firewall on your OSX has added Roon as an exception? You can use these instructions from Apple to verify this. If you have any Antivirus software in place or firewall app such as “Bullguard” or “Little Snitch” I would try to temporarily disable those as well to see if there is a change in behavior. Please let me know if this helps.