Glad to hear the issue cleared after a couple of restarts. Since Roon Server was running on the same Windows 11 PC as the Remote, that points more toward a local startup or discovery hiccup than a network design problem.
If it happens again, the two things we’d want to check are whether the Roon Server service is actually starting in Windows and whether anything on the machine is briefly holding up local connections right after boot, such as security software or startup load. A full PC restart clearing it does make that a useful clue.
To help us keep an eye on it, could you let us know whether Roon starts normally after a single reboot, or whether it only comes back after more than one restart? If it returns, please note the exact local time and what you see in the Roon app, and we can take a closer look from there.