In FreeNAS 11.3-RC1, links in tooltips/popups use the domain ixsystems.com/documentation/
When clicking on the documentation link users receive a 404.
It may be that ixystems DNS is not configured to redirect all www. requests to . or perhaps something has changed in either the URLs or the documentation links.
Adding www. at the start of URLs means the browser is able to display the correct documentation page.