Keep on getting HTTP error 500 in PHP

oauth
php
api

#1

I am trying to connect to Twitter API using OAuth but I keep on getting “localhost is currently unable to handle this request” HTTP ERROR 500. Here is my code:

<?php
require "twitteroauth/autoload.php";

use Abraham\TwitterOAuth\TwitterOAuth;

$consumer_key = "";       //left blank here intentionally.
$consumer_secret = "";
$access_token = "";
$access_token_secret = "";

$connection = new TwitterOAuth($consumer_key, $consumer_secret, $access_token, $access_token_secret);
$content = $connection->get("account/verify_credentials");
print_r($content);
    ?>

What could be the issue?