Why do I have no information on referring sites?

30 days of data, zero information about what websites the visitors came from. What’s the problem here? Why is there no documentation for this tool?

Someone reporting this issue earlier said their security plugin was the problem, but I’m not just going to disable my security plugin, so I need details about what specific setting needs to change. Why is there no documentation for this tool?

If there’s a problem preventing the collection of certain statistics, could your plugin not either detect the problem and display a useful notice, or at least display a “possible reasons” static text when it says there’s no data?