Facebook SDK PHP 5.0 getLoginUrl () Error 500

I am trying to use the examples provided in Facebook PHP SDK 5.0 to log into Facebook. I am returning 500 Internal Server Error. I am using the Baby plan from HostGator which is running Php 5.5.27 PHP INFO . Is there any configuration I will need to add to my server to get everything to work?

login.php

<?php
session_start();
// Include the required dependencies.
require_once( 'vendor/autoload.php' );
// Initialize the Facebook PHP SDK v5.
$fb = new Facebook\Facebook([
  'app_id'                => '495994870548274',
  'app_secret'            => '593f18b375c9e23d34b9794136cf7158',
  'default_graph_version' => 'v2.3',
]);

$helper = $fb->getRedirectLoginHelper();

$permissions = ['email']; // Optional permissions
$loginUrl = $helper->getLoginUrl('http://techcomsgb.com/kidneytest/login-callback.php', $permissions);

echo '<a href="' . $loginUrl . '">Log in with Facebook!</a>'

      

        
        
        
      

    

login-callback.php

<?php
session_start();

// Include the required dependencies.
require_once( 'vendor/autoload.php' );



// Initialize the Facebook PHP SDK v5.
$fb = new Facebook\Facebook([
  'app_id'                => '495994870548274',
  'app_secret'            => '593f18b375c9e23d34b9794136cf7158',
  'default_graph_version' => 'v2.3',
]);

$helper = $fb->getRedirectLoginHelper();

try {
  $accessToken = $helper->getAccessToken();
} 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;
}

if (! isset($accessToken)) {
  if ($helper->getError()) {
    header('HTTP/1.0 401 Unauthorized');
    echo "Error: " . $helper->getError() . "\n";
    echo "Error Code: " . $helper->getErrorCode() . "\n";
    echo "Error Reason: " . $helper->getErrorReason() . "\n";
    echo "Error Description: " . $helper->getErrorDescription() . "\n";
  } else {
    header('HTTP/1.0 400 Bad Request');
    echo 'Bad request';
  }
  exit;
}

// Logged in
echo '<h3>Access Token</h3>';
var_dump($accessToken->getValue());

// The OAuth 2.0 client handler helps us manage access tokens
$oAuth2Client = $fb->getOAuth2Client();

// Get the access token metadata from /debug_token
$tokenMetadata = $oAuth2Client->debugToken($accessToken);
echo '<h3>Metadata</h3>';
var_dump($tokenMetadata);

// Validation (these will throw FacebookSDKException when they fail)
$tokenMetadata->validateAppId($config['app_id']);
// If you know the user ID this access token belongs to, you can validate it     here
//$tokenMetadata->validateUserId('123');
$tokenMetadata->validateExpiration();

if (! $accessToken->isLongLived()) {
  // Exchanges a short-lived access token for a long-lived one
  try {
    $accessToken = $oAuth2Client->getLongLivedAccessToken($accessToken);
  } catch (Facebook\Exceptions\FacebookSDKException $e) {
    echo "<p>Error getting long-lived access token: " . $helper-    >getMessage() . "</p>\n\n";
    exit;
  }

  echo '<h3>Long-lived</h3>';
  var_dump($accessToken->getValue());
}

$_SESSION['fb_access_token'] = (string) $accessToken;

// User is logged in with a long-lived access token.

      

        
        
        
      

    

// You can redirect them to a member-only page. // header ('Location: https://example.com/members.php ');