Piwik 2.4.1
When clicking on setting under user, and manage websites. No websites are listed, I just get a Loading Data …
I says - You currently have access to 0 websites.
Even though I have 16 sites and logged in as super user.
maybe you see some error message in your server error log file?
Otherwise in your browser, with the developer console, maybe you see some error such as 404?