ErrorCurlException：7：无法连接到255.255.255.255：网络无法访问

Question

I am getting this error in my PHP code:

ErrorCurlException: 7: Failed to connect to 255.255.255.255: Network is unreachable

Here is my code:

require_once 'src/facebook.php'; //include the facebook php sdk
$facebook = new Facebook(array(
    'appId'  => '*************',    //app id
    'secret' => '**********************', // app secret
));

$user = $facebook->getUser();

if ($user) { // check if current user is authenticated
    try {
        // Proceed knowing you have a logged in user who's authenticated.

        $user_profile = $facebook->api('/me');  //get current user's profile information using open graph
        $email = $user_profile['email'];
        echo"<script>alert(\"$name\");</script>";
    } catch(Exception $e)    {
        $name="Error".$e;
    }
}
echo"<script>alert(\"$name\");</script>";
?>

The same code is working on a different page. I am just a beginner and don't know much about FB API.