The navigation does not show its content for admin users. It displays a kind of symbol showing it’s running…
I guess it is a problem of right access, but I have not succeeded in solving this issue until now. Hell will be appreciated.
What version of XWiki are you using? You could check the Network tab from the browser’s developer tools to see which HTTP requests are failing and why.
The only issue I know that is close to what you describe is Loading..., but it should be fixed in your version of XWiki. I doubt it’s a problem of access rights if this problem reproduces only for administrators. You really need to check the HTTP request used to fetch the tree contents, using the browser’s developer tools.