Anchor links working but not smooth

I installed the plugin. For the link I did this: “Pagina 2” and the target looks like this: “pagina2“. The link leads to the target but without smooth scrolling, immediately. On the other hand, the arrow to scroll up appears in the lower right corner and scrolling back up works smoothly. What more should I do?

http://wordpress.org/plugins/jquery-smooth-scroll/