How to resolve Paypal Error - The link you have used to enter the PayPal system is invalid. Please review the link and try again?

Question

I am following the instructions in this tutorial: http://code.tutsplus.com/tutorials/using-paypals-instant-payment-notification-with-php--net-3271

1. I already have an account. It is a personal Paypal account but I guess I can use it otherwise there won't be any settings for turning IPN on or off etc.
2. I enabled IPN and set the notification URL as domain.com/ipn.php

3. I also created a Paypal button and here is its code:

    <form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post" target="_top"> <input type="hidden" name="cmd" value="_s-xclick"> <input type="hidden" name="hosted_button_id" value="3B85B5WNMDLUU"> <input type="submit" name="submit" value="Paypal Sandbox"> </form> 

4. I used the following code for ipn.php

    $req = 'cmd=_notify-validate'; foreach ($_POST as $key => $value) { $value = urlencode(stripslashes($value)); $req .= "&$key=$value"; } $header = "POST /cgi-bin/webscr HTTP/1.0\\r\\n"; $header .= "Content-Type: application/x-www-form-urlencoded\\r\\n"; $header .= "Content-Length: " . strlen($req) . "\\r\\n\\r\\n"; $fp = fsockopen ('www.sandbox.paypal.com', 80, $errno, $errstr, 30); if (!$fp) {} else { fputs ($fp, $header . $req); while (!feof($fp)) { $res = fgets ($fp, 1024); if (strcmp ($res, "VERIFIED") == 0) { // PAYMENT VALIDATED & VERIFIED! mail("Email Address", 'Payment Paypal', Used Email Address - $_POST['payer_email'], 'Website'); } 

After I click on payment button and login I get the error

   The link you have used to enter the PayPal system is invalid. Please review the link and try again.

Is there any error in the script?

Answer 1

The error could be due to an issue with the button created. Go to developer.paypal.com , create a Business Sandbox account.

Then go to www.sandbox.paypal.com and login with your account created, and create a button from your account.

Then, copy and paste the whole code generated for you and paste it in your webpage. Everything should work fine once you click the button and login with your sandbox buyer account to make a test payment.

IPN code seems to be not completed. Please use this instead:

<?php
// CONFIG: Enable debug mode. This means we'll log requests into 'ipn.log' in the same directory.
// Especially useful if you encounter network errors or other intermittent problems with IPN (validation).
// Set this to 0 once you go live or don't require logging.
define("DEBUG", 1);
// Set to 0 once you're ready to go live
define("USE_SANDBOX", 1);
define("LOG_FILE", "./ipn.log");
// Read POST data
// reading posted data directly from $_POST causes serialization
// issues with array data in POST. Reading raw POST data from input stream instead.
$raw_post_data = file_get_contents('php://input');
$raw_post_array = explode('&', $raw_post_data);
$myPost = array();
foreach ($raw_post_array as $keyval) {
    $keyval = explode ('=', $keyval);
    if (count($keyval) == 2)
        $myPost[$keyval[0]] = urldecode($keyval[1]);
}
// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';
if(function_exists('get_magic_quotes_gpc')) {
    $get_magic_quotes_exists = true;
}
foreach ($myPost as $key => $value) {
    if($get_magic_quotes_exists == true && get_magic_quotes_gpc() == 1) {
        $value = urlencode(stripslashes($value));
    } else {
        $value = urlencode($value);
    }
    $req .= "&$key=$value";
}
// Post IPN data back to PayPal to validate the IPN data is genuine
// Without this step anyone can fake IPN data
if(USE_SANDBOX == true) {
    $paypal_url = "https://www.sandbox.paypal.com/cgi-bin/webscr";
} else {
    $paypal_url = "https://www.paypal.com/cgi-bin/webscr";
}
$ch = curl_init($paypal_url);
if ($ch == FALSE) {
    return FALSE;
}
curl_setopt($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_SSL_VERIFYPEER, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
if(DEBUG == true) {
    curl_setopt($ch, CURLOPT_HEADER, 1);
    curl_setopt($ch, CURLINFO_HEADER_OUT, 1);
}
// CONFIG: Optional proxy configuration
//curl_setopt($ch, CURLOPT_PROXY, $proxy);
//curl_setopt($ch, CURLOPT_HTTPPROXYTUNNEL, 1);
// Set TCP timeout to 30 seconds
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
// CONFIG: Please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set the directory path
// of the certificate as shown below. Ensure the file is readable by the webserver.
// This is mandatory for some environments.
//$cert = __DIR__ . "./cacert.pem";
//curl_setopt($ch, CURLOPT_CAINFO, $cert);
$res = curl_exec($ch);
if (curl_errno($ch) != 0) // cURL error
    {
    if(DEBUG == true) { 
        error_log(date('[Y-m-d H:i e] '). "Can't connect to PayPal to validate IPN message: " . curl_error($ch) . PHP_EOL, 3, LOG_FILE);
    }
    curl_close($ch);
    exit;
} else {
        // Log the entire HTTP response if debug is switched on.
        if(DEBUG == true) {
            error_log(date('[Y-m-d H:i e] '). "HTTP request of validation request:". curl_getinfo($ch, CURLINFO_HEADER_OUT) ." for IPN payload: $req" . PHP_EOL, 3, LOG_FILE);
            error_log(date('[Y-m-d H:i e] '). "HTTP response of validation request: $res" . PHP_EOL, 3, LOG_FILE);
        }
        curl_close($ch);
}
// Inspect IPN validation result and act accordingly
// Split response headers and payload, a better way for strcmp
$tokens = explode("\r\n\r\n", trim($res));
$res = trim(end($tokens));
if (strcmp ($res, "VERIFIED") == 0) {
    // check whether the payment_status is Completed
    // check that txn_id has not been previously processed
    // check that receiver_email is your PayPal email
    // check that payment_amount/payment_currency are correct
    // process payment and mark item as paid.
    // assign posted variables to local variables
    //$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'];

    if(DEBUG == true) {
        error_log(date('[Y-m-d H:i e] '). "Verified IPN: $req ". PHP_EOL, 3, LOG_FILE);
    }
} else if (strcmp ($res, "INVALID") == 0) {
    // log for manual investigation
    // Add business logic here which deals with invalid IPN messages
    if(DEBUG == true) {
        error_log(date('[Y-m-d H:i e] '). "Invalid IPN: $req" . PHP_EOL, 3, LOG_FILE);
    }
}
?>