If you browse this forum you notice MANY, too many, users have issues where they lose connection to the Roon Server after searching something, be it on Windows, MacOS, Linux or NAS … for example…
https://community.roonlabs.com/t/roon-search-extremely-slow-how-to-fix-it-build-1353/
… this loss of connexion is a symptom of a deeper issue than firewall settings.