Since you’re running macOS, the behavior you’re seeing is consistent with the newer, stricter Local Network permission controls in the recent macOS releases.
Please try the following steps:
Open macOS System Settings → Privacy & Security → Local Network
Make sure Roon and Roon Server are both enabled
Even if they are already enabled, please toggle them off and back on
Fully quit Roon Server from the macOS menu bar / task bar
Reboot your Mac
After reboot, launch Roon again and check if the Roon is avaliable again.
Once these permissions are refreshed and the system restarted, your audio devices should reappear.
Please let us know if the issue persists after these steps, and we’ll continue from there.
If you’re running a MacOS version earlier than Sequoia or Tahoe, you might not see the specific steps under Privacy & Security mentioned above.
Earlier MacOS versions sometimes still block Roon at the level of the MacOS firewall itself, which you’d need to check in System Settings.
I’d additionally check that the Roon GUI (the remote) isn’t running a separate version from the server. Reinstalling Roon from the website will update to the latest version without affecting your database.