basic authentication

I’m trying to connect via basic auth using this script:

<?php
$username = "name";
$password = "pass";

$args = array(
    'headers' => array(
        'Authorization' => 'Basic ' . base64_encode( $username . ':' . $password ),
    ),
);
echo '<pre>';
echo http_get ( 'https://site.com/dev/wp/wp-json/users/me', $args );
echo '</pre>';
?>

The response I get is this:

HTTP/1.1 401 Unauthorized
Date: Mon, 25 May 2015 18:24:51 GMT
Server: Apache/2.2.24 (Unix) mod_hive/5.0 mod_ssl/2.2.24 OpenSSL/1.0.0-fips mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 mod_fcgid/2.3.6
X-Powered-By: PHP/5.4.33
X-Pingback: https://www.betypist.com/dev/wp/xmlrpc.php
X-Content-Type-Options: nosniff
Host-Header: 192fc2e7e50945beb8231a492d6a8024
Transfer-Encoding: chunked
Content-Type: application/json; charset=UTF-8

4c
[{"code":"json_not_logged_in","message":"You are not currently logged in."}]
0

Any ideas on why?