XML : PHP RSS parser - - not working

Hello I'm working on parsing this feed and cannot seem to get it to work

  <?php    

$url = "http://insite.unthsc.edu/dailynews/category/campus-news/feed/";

$xml = simplexml_load_file($url);

print_r($xml); ?>

I get this currently when I output pre I've done this before for other feeds and xml files but cannot for the life of me figure out why it is not working this time.

Thanks