Get user email from Facebook Web SDK API v5 - php

Question

I need your help.
I am using Kohana 3.0.4 framework for my web app and i want to use facebook login so i am using the Facebook Web SDK v5. I get every information from the the user profile except the user email. In my login action this what i did:
$fb = new Facebook\Facebook([
'app_id' => 'xxxxxx',
'app_secret' => 'xxxxxxx',
'default_graph_version' => 'v2.8',
]);
$helper = $fb->getRedirectLoginHelper();
$permissions = ['email', 'user_birthday', 'public_profile']; // optional
$callback = 'http://www.example.com';
$loginUrl = $helper->getLoginUrl($callback, $permissions); echo "<a href='.$loginUrl.'>Login With Facebook</a>";
then in the redirected action:
# login-callback.php
$fb = new Facebook\Facebook([
'app_id' => '1200538793346947',
'app_secret' => '3cf44820ffae5f16c8122174701a558f',
'default_graph_version' => 'v2.8',
]);
// Use one of the helper classes to get a Facebook\Authentication\AccessToken entity.
$helper = $fb->getRedirectLoginHelper();
// $helper = $fb->getJavaScriptHelper();
// $helper = $fb->getCanvasHelper();
// $helper = $fb->getPageTabHelper();
try {
$accessToken = $helper->getAccessToken();
// Get the \Facebook\GraphNodes\GraphUser object for the current user.
// If you provided a 'default_access_token', the '{access-token}' is optional.
$response = $fb->get('/me?fields=email,name,birthday,gender', $accessToken);
} catch(\Facebook\Exceptions\FacebookResponseException $e) {
// When Graph returns an error
echo 'Graph returned an error: ' . $e->getMessage();
exit;
} catch(\Facebook\Exceptions\FacebookSDKException $e) {
// When validation fails or other local issues
echo 'Facebook SDK returned an error: ' . $e->getMessage();
exit;
}
$me = $response->getGraphUser();
echo 'Logged in as ' . $me->getName(). ' ' . $me->getId() . ' '. $me->getGender() . ' '. $me->getEmail() . '<br />';
print_r($me->getBirthday());
Please i need help because i want to also get the user email. Thanks in advance.