Не удалось создать предварительную подписку с помощью PHP SDK

у меня возникли проблемы с созданием предварительного утверждения: это мой код:

$mp = new MP ("CLIENT_ID", "CLIENT_SECRET");
$data = array(
        'order_frequency' => 1,
        'order_frequency_type' => 'months',
        'currency_code' => "ARS",
        'customer_email' => '[email protected]',
        'order_reference' => 'REF-2424',
        'amount' => 5000
    );
$preapproval_data = array(
        'payer_email' => $data['customer_email'],
        'back_url' => "http://www.my-sitesss.com",
        'reason' =>"Monthly subscription to premium package",
        'external_reference' => 'dsfdsfds',
        "auto_recurring" => array(
            "frecuency" => $data['order_frequency'],
            "frequency_type" => $data['order_frequency_type'],
                "transaction_amount" => $data['amount'],
                "currency_id" => $data['currency_code']
                )
);
$preapproval = $mp->create_preapproval_payment($preapproval_data);

кроме того, я попробовал с другим SDK:

    \MercadoPago\Sdk::initialize(); 
    $config = \MercadoPago\Sdk::config(); 
    $config->set('ACCESS_TOKEN', '..........................');
    $preapproval_data = new \MercadoPago\Preapproval();
    $preapproval_data->payer_email = $data['customer_email'];
    $preapproval_data->back_url = "http://www.my-site.com";
    $preapproval_data->reason = "Monthly subscription to premium package";
    $preapproval_data->external_reference = $data['order_reference'];
    $preapproval_data->frecuency = $data['order_frequency'];
    $preapproval_data->frequency_type = $data['order_frequency_type'];
    $preapproval_data->transaction_amount = $data['amount'];
    $preapproval_data->currency_id = $data['currency_code'];
    $preapproval_data->auto_recurring = array( 
        "frecuency" => 1,
        "frequency_type" => "months",
            "transaction_amount" => 60,
            "currency_id" => "ARS",
            "start_date" => "2018-01-17T14:58:11.778-03:00",
            "end_date" => "2020-06-17T14:58:11.778-03:00"
      );
  $preapproval_data->save();

и оба возвращаются ко мне:

the parameters frequency, frequency_type, transaction_amount and currency_id are required in the recurring payments scheme

даже используя прямой пример SDK здесь

Заранее спасибо