PayPal IPN订阅无效，但付款已处理

Question

我从未进行过订阅贝宝处理，因此不确定我做错了什么。在paypal帐户中正确设置了paypal ipn网址，下面的代码是我拼凑而成的。它在沙盒上完美运行，但沙盒不支持订阅。

我通过购买进行了实际测试，但无法正常工作。付款在Paypal上处理，状态未验证，但是在必须接收IPN的页面上没有任何反应。我将信息转储到文件中进行测试，这样我可以看到发生了什么，但是什么也没发生，没有使用信息创建文件，这必须表示没有发送IPN吗？

任何帮助表示赞赏！

$enableSandbox = false;
$paypalUrl = $enableSandbox ? 'https://ipnpb.sandbox.paypal.com/cgi-bin/webscr' : 'https://ipnpb.paypal.com/cgi-bin/webscr';

    function verifyTransaction($data) {
        global $paypalUrl;

        $req = 'cmd=_notify-validate';
        foreach ($data as $key => $value) {
            $value = urlencode(stripslashes($value));
            $value = preg_replace('/(.*[^%^0^D])(%0A)(.*)/i', '${1}%0D%0A${3}', $value); // IPN fix
            $req .= "&$key=$value";
        }

        $ch = curl_init($paypalUrl);
        curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
        curl_setopt($ch, CURLOPT_SSLVERSION, 6);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
        curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
        curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
        $res = curl_exec($ch);

        if (!$res) {
            $errno = curl_errno($ch);
            $errstr = curl_error($ch);
            curl_close($ch);
            throw new Exception("cURL error: [$errno] $errstr");
        }

        $info = curl_getinfo($ch);

        // Check the http response
        $httpCode = $info['http_code'];
        if ($httpCode != 200) {
            throw new Exception("PayPal responded with http code $httpCode");
        }

        curl_close($ch);

        //return $res === 'VERIFIED';
        return $res;
    }

        // Handle the PayPal response.

        // Assign posted variables to local data array.
        $data = [
            'item_name' => $_POST['item_name'],
            'item_number' => $_POST['item_number'],
            'payment_status' => $_POST['payment_status'],
            'payment_amount' => $_POST['mc_gross'],
            'payment_currency' => $_POST['mc_currency'],
            'txn_id' => $_POST['txn_id'],
            'receiver_email' => $_POST['receiver_email'],
            'payer_email' => $_POST['payer_email'],
            'payer_id' => $_POST['payer_id'],
            'custom' => $_POST['custom'],
            'txn_type' => $_POST['txn_type'],
            'subscr_id' => $_POST['subscr_id'],
            'txn_id' => $_POST['txn_id'],
        ];

        if (verifyTransaction($_POST)) {  
            if($data['receiver_email'] == "PAYPAL ACCOUNT EMAIL OMMITTED"){                
                if($data['payment_status'] == "Completed" || $data['txn_type'] == "subscr_payment"){
                    if($data['custom'] != ""){
                        //code removed
                    }
                }
            }
        }