Hello @Mark_Sealey
Thank you for the update.
If this happens again, would you kindly try also retriggering the Local Area Network access on your Mac?
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 devices is avaliable again.