Problem bei GET API Call

Also mein code ist wie folgt

 

class ApiClient
{
    const METHOD_GET = 'GET';
    const METHOD_PUT = 'PUT';
    const METHOD_POST = 'POST';
    const METHOD_DELETE = 'DELETE';
    protected $validMethods = [
        self::METHOD_GET,
        self::METHOD_PUT,
        self::METHOD_POST,
        self::METHOD_DELETE,
    ];
    protected $apiUrl;
    protected $cURL;

    public function __construct($apiUrl, $username, $apiKey)
    {
        $this->apiUrl = rtrim($apiUrl, '/') . '/';
        //Initializes the cURL instance
        $this->cURL = curl_init();
        curl_setopt($this->cURL, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($this->cURL, CURLOPT_FOLLOWLOCATION, false);
        curl_setopt($this->cURL, CURLOPT_USERAGENT, 'Shopware ApiClient');
        curl_setopt($this->cURL, CURLOPT_HTTPAUTH, CURLAUTH_DIGEST);
        curl_setopt($this->cURL, CURLOPT_USERPWD, $username . ':' . $apiKey);
        curl_setopt(
            $this->cURL,
            CURLOPT_HTTPHEADER,
            ['Content-Type: application/json; charset=utf-8']
        );
    }

    public function call($url, $method = self::METHOD_GET, $data = [], $params = [])
    {
        if (!in_array($method, $this->validMethods)) {
            throw new Exception('Invalid HTTP-Methode: ' . $method);
        }
        $queryString = '';
        if (!empty($params)) {
            $queryString = http_build_query($params);
        }
        $url = rtrim($url, '?') . '?';
        $url = $this->apiUrl . $url . $queryString;
        $dataString = json_encode($data);
        curl_setopt($this->cURL, CURLOPT_URL, $url);
        curl_setopt($this->cURL, CURLOPT_CUSTOMREQUEST, $method);
        curl_setopt($this->cURL, CURLOPT_POSTFIELDS, $dataString);
        $result = curl_exec($this->cURL);
        $httpCode = curl_getinfo($this->cURL, CURLINFO_HTTP_CODE);

        return $this->prepareResponse($result, $httpCode);
    }

    public function get($url, $params = [])
    {
        return $this->call($url, self::METHOD_GET, [], $params);
    }

    public function post($url, $data = [], $params = [])
    {
        return $this->call($url, self::METHOD_POST, $data, $params);
    }

    public function put($url, $data = [], $params = [])
    {
        return $this->call($url, self::METHOD_PUT, $data, $params);
    }

    public function delete($url, $params = [])
    {
        return $this->call($url, self::METHOD_DELETE, [], $params);
    }

    protected function prepareResponse($result, $httpCode)
    {
        echo "HTTP: $httpCode";
        if (null === $decodedResult = json_decode($result, true)) {
            $jsonErrors = [
                JSON_ERROR_NONE => 'No error occurred',
                JSON_ERROR_DEPTH => 'The maximum stack depth has been reached',
                JSON_ERROR_CTRL_CHAR => 'Control character issue, maybe wrong encoded',
                JSON_ERROR_SYNTAX => 'Syntaxerror',
            ];
            echo 'Could not decode json';
            echo 'json_last_error: ' . $jsonErrors[json_last_error()];
            echo 'Raw:';
            echo '' . print_r($result, true) . '';

            return;
        }
        if (!isset($decodedResult['success'])) {
            echo 'Invalid Response';

            return;
        }
        if (!$decodedResult['success']) {
            echo 'No Success';
            echo '' . $decodedResult['message'] . '';
            if (array_key_exists('errors', $decodedResult) && is_array($decodedResult['errors'])) {
                echo '' . join('', $decodedResult['errors']) . '';
            }

            return;
        }
        echo 'Success';
        if (isset($decodedResult['data'])) {
            echo '' . print_r($decodedResult['data'], true) . '';
        }

        return $decodedResult;
    }
}

$client = new ApiClient(
    //URL of shopware REST server
    'https://www.xxxx.de/api',
    //Username
    'xxxx',
    //User's API-Key
    'xxxx'
);


$client->get('articles/570');
echo "";
var_dump($client);

wenn ich die shopid übergebe bleibt der fehler.

HTTP: 404
No Success

Resource not found

object(ApiClient)#1 (3) {
  ["validMethods":protected]=>
  array(4) {
    [0]=>
    string(3) "GET"
    [1]=>
    string(3) "PUT"
    [2]=>
    string(4) "POST"
    [3]=>
    string(6) "DELETE"
  }
  ["apiUrl":protected]=>
  string(41) "https://www.xxxx.de/api/articles/"
  ["cURL":protected]=>
  resource(2) of type (curl)
}