连接以获得codeigniter的响应

I need to connect to get response with codeigniter. I use library https://github.com/robertstaddon/GetResponse-PHP-Wrapper/blob/master/PHPwrapper/GetResponseAPI.class.php

my conteroller is :

class GetResponse extends CI_Controller {

function __construct() {
    parent::__construct();

    $params = array('$apiKey'=>'f19198cd268a8cf931ad5c7266673138') ;
    $this->load->library('GetResponseAPI',$params,'api');
}

public function index()
{
     //Connection Testing
    $ping = $this->api->ping();
    $data['ping'] = $ping;
    $this->load->view('getResponse/test',$data);

}
}

What I get is :

A PHP Error was encountered

Severity: User Error

Message: API call failed. Server returned status code 204

Filename: libraries/GetResponseAPI.php

Line Number: 326

Backtrace:

File: C:\projects\funnels\application\libraries\GetResponseAPI.php Line: 326 Function: trigger_error

File: C:\projects\funnels\application\libraries\GetResponseAPI.php Line: 68 Function: execute

File: C:\projects\funnels\application\controllers\GetResponse.php Line: 25 Function: getAccountInfo

File: C:\projects\funnels\index.php Line: 292 Function: require_once