Answer
Check whether the URL address configured for the navigation matches the client the lobby is actually being viewed from — an IEE-hosted lobby needs an IEE-style navigation URL, while a lobby viewed through Aurena needs the Aurena web-access URL with its own filter syntax; the two URL/filter formats aren't interchangeable, and giving an Aurena-style address where an IEE address is expected (or vice versa) is enough to prevent the link from rendering as clickable at all. Each client has its own dedicated navigation-configuration documentation covering the correct URL and filter syntax to use.