PayPal DoDirectPayment在没有cvv的情况下工作

Question

您好我在我的网站上实施PayPal DoDirectPayment，我想要求过期日期和CVV，但是没有带有此警告的人付款“此交易已获批准。但是，提供的卡安全码太少，太多或无效字符类型，但根据您的帐户选项设置，在审批流程中不需要“

我正在使用PHP。

我的代码是

$api_endpoint = 'https://api-3t.sandbox.paypal.com/nvp';
$request = array
            (
                'METHOD'                => 'DoDirectPayment',
                'USER'                  => 'sell3_api1.pay.com',
                'PWD'                       => '75DQHCABLDFSDF',
                'SIGNATURE'         => 'AFcWxV21C7fd0asdasdCpasdsdAtxzafSFsaKZ3unSUBjX9r-',
                'VERSION'               => '55.0',
                'PAYMENTACTION' => 'Sale',
                'FIRSTNAME'         => $current_user->user_login,
                'LASTNAME'          => '.',
                'IPADDRESS'         => $_SERVER['REMOTE_ADDR'],
                'ACCT'                  => $acct,
                'CREDITCARDTYPE'=> 
                'EXPDATE'               => $month.$year,
                'CVV2'                  => $cvv,
                'AMT'                       => $amt,
                'CURRENCYCODE'  => 'USD',
            );

    $nvp_string = '';

    foreach ($request as $key => $value) {
        $nvp_string .= '&'.$key.'='.urlencode($value);
    }

    $curl = curl_init();
                    curl_setopt($curl, CURLOPT_VERBOSE, 1);
                    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);
                    curl_setopt($curl, CURLOPT_TIMEOUT, 30);
                    curl_setopt($curl, CURLOPT_URL, $api_endpoint);
                    curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
                    curl_setopt($curl, CURLOPT_POSTFIELDS, $nvp_string);

    $result = curl_exec($curl);
    curl_close($curl);
    parse_str($result);

我该如何解决呢。