Connection failure to vaadin sampler page

Hi… I am not able to open sampler page. It is throwing following error:-

The following error was encountered while trying to retrieve the URL:

   Connection to failed.

The system returned: (110) Connection timed out

The remote host or network may be down. Please try the request again.

Your cache administrator is webmaster.

Can any one please let me know what is the issue and how can I open this page.