Services returns false

I'm trying to make a new site in aegir via a service. But when I send my request it returns a boolean false / empty array.

I can login with the same service. No problem there. The resource is active and the permissions are also right.

Anyone an idea?

// Server REST - node.create
$request_url = 'http://host/service/hosting_site/';

// node data
$node_data = array(
'url'     => 'test',
    'data'        => array(    // REQUIRED FIELDS
                     'title'                   => 'test',
                        'type'                    => 'site',
                        'profile'                 => 'hostmaster',
                      'platform'                => 'hostmaster',
                      'site_language'           => 'nl',
                      'db_server'               => 'localhost',
                      'client'              => 'api',
                 ),
);
$node_data = http_build_query($node_data);

// Define cookie session
$cookie_session = $logged_user->session_name . '=' . $logged_user->sessid;

// cURL
$curl = curl_init($request_url);
curl_setopt($curl, CURLOPT_HTTPHEADER, array('Accept: application/json')); // Accept JSON response
curl_setopt($curl, CURLOPT_POST, 1); // Do a regular HTTP POST
curl_setopt($curl, CURLOPT_POSTFIELDS, $node_data); // Set POST data
curl_setopt($curl, CURLOPT_HEADER, FALSE);  // Ask to not return Header
curl_setopt($curl, CURLOPT_COOKIE, $cookie_session); // use the previously saved session
curl_setopt($curl, CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($curl, CURLOPT_FAILONERROR, TRUE);

$response = curl_exec($curl);
$http_code = curl_getinfo($curl, CURLINFO_HTTP_CODE);

if ($http_code == 200) {
  // Convert json response as array
  $node = json_decode($response);
}
else {
  // Get error msg
  $http_message = curl_error($curl);
  die($http_message);
}

print_r('node: ');
print_r($node);

curl_close($curl);
unset($curl);

return:

loggedin node: Array ( [0] => )