Slideshows require the Flash Player and a browser with Javascript support.

Have you enabled Flash and Javascript in the browser?

For example, Safari by default will disable Flash depending on your security settings. For more information, please review: https://helpx.adobe.com/flash-player/kb/enabling-flash-player-safari.html

Oh, and I’ll also add that if you are building a site where mobile users are a concern, Flash is not supported in any iOS devices (iPads, iPhones, iPods). So, if that’s a concern for you, you may want to find a non-Flash based option.

Of course I enabled it. Is that possible error that server or other configuration?