电子邮件没有出现在Facebook PHP SDK中

这是facebook php sdk中的登录系统，会发生什么情况，它要求基本权限，然后当用户通过他的Facebook帐户允许时，它会存储他的Facebook ID和电子邮件，然后通过会话在索引中显示此fbid和电子邮件，但是它无法正常工作，尽管fbid来了坚果电子邮件没有来，它显示为空白

 <?php
 session_start();
 require_once("autoload.php"); 
 require_once('Facebook/FacebookSession.php');
 require_once('Facebook/FacebookRedirectLoginHelper.php');
 require_once('Facebook/FacebookRequest.php');
 require_once('Facebook/FacebookResponse.php');
 require_once('Facebook/FacebookSDKException.php');
 require_once('Facebook/FacebookRequestException.php');
 require_once('Facebook/FacebookAuthorizationException.php');
 require_once('Facebook/GraphObject.php');
 require_once('Facebook/GraphUser.php');
 require_once('Facebook/GraphSessionInfo.php');
 require_once( 'Facebook/HttpClients/FacebookHttpable.php' );
 require_once( 'Facebook/HttpClients/FacebookCurl.php' );
 require_once( 'Facebook/HttpClients/FacebookCurlHttpClient.php' );
 require_once( 'Facebook/Entities/AccessToken.php' );
 require_once( 'Facebook/Entities/SignedRequest.php' );    
 use Facebook'FacebookSession; use Facebook'FacebookRedirectLoginHelper;
 use Facebook'FacebookRequest; use Facebook'FacebookResponse;
 use Facebook'FacebookSDKException; use Facebook'FacebookRequestException;
 use Facebook'FacebookAuthorizationException; use Facebook'GraphObject;
 // init app with app id and secret
 FacebookSession::setDefaultApplication(     '     332325566667346','30adsfsdf7sdf87df6s7df87sdf76dsfd16' );
 // login helper with redirect_uri
 $helper = new           FacebookRedirectLoginHelper('http://localhost/bb/fbconfig.php'     );
 try {
   $session = $helper->getSessionFromRedirect();
 } catch( FacebookRequestException $ex ) {
   // When Facebook returns an error
 } catch( Exception $ex ) {
 }
 // see if we have a session
 if ( isset( $session ) ) {
   $request = new FacebookRequest( $session, 'GET', '/me' );
   $response = $request->execute();
   $graphObject = $response->getGraphObject();
     $email = $graphObject->getProperty('email');          
   echo $email;
 } else {
   $loginUrl = $helper->getLoginUrl();
  header("Location: ".$loginUrl);
 }
 ?>