If you can, always test out setting up a direct ethernet connection to your router - it can help eliminate any potential network-related issues, and ultimately will provide you a better and more stable roon experience.
Can you please navigate to macOS System Settings > Privacy & Security > Local Network , and make sure Roon is allowed. If it is already enabled, toggle it off and on again. Then reboot your Mac, and see if the same issue persists.
This is an issue that has been lingering with the recent Mac Sequoia update, we’re hoping Apple pushes a fix with the next Sequoia update (15.4), which should be happening this week.
I had tried switching the permissions on and off, to no effect before.
However, this time, I closed Roon before performing this, and it worked.
My MacBook Pro was still not being recognised as an endpoint, though. I performed the same task on the MBP and everything started working as normal again.
Restarting RoonServer also re-initiates a network discovery cycle - if this happens again, I recommend toggling the Privacy settings on/off for local network access as usual, and then hitting the “refresh” button (looped arrow) in Roon Settings → Audio.
You can additionally change the Private WiFi Address from “Rotating” to “Fixed” in both Macs’ WiFi Details settings page. This should help retain a connection to RAATServer on these MacOS instances. Thanks!