php paypal returns INVALID on live - php

Question

So I am working on a small site which takes a single payment per user.
When I do payments through the sandbox, if the payment is a success then i always get a IPN response and am able to use that to update my DB
BUT when using live even if paypal says it was a success the IPN returns INVALID
I have looked around for an answer and people have been saying make sure you are using paypal.com and not sandbox.paypal.com, I have done all the suggestions but still no luck.
A working answer to this would be much appreciated!
Here is my code:
This is the html form:
<form class="paypal" action="payments.php" method="post" id="paypal_form" target="_blank">
<input type="hidden" name="cmd" value="_xclick" />
<input type="hidden" name="no_note" value="1" />
<input type="hidden" name="lc" value="UK" />
<input type="hidden" name="currency_code" value="GBP" />
<input type="hidden" name="first_name" value="Customer's First Name" />
<input type="hidden" name="last_name" value="Customer's Last Name" />
<input type="hidden" name="payer_email" value="customer#example.com" />
<input type="hidden" name="item_number" value="123456" / >
<input type="hidden" name="invoice" value="<?php echo $invoice ?>" / >
<input class="submit" type="submit" name="submit" value="Start Payment Process"/>
</form>
This code starts the payment:
<?php
// Database variables
$servername = "localhost";
$username = "un";
$password = "pw";
$dbname = "dbn";
// PayPal settings
$paypal_email = 'email#email.com';
$return_url = 'http://domain.co.uk/paypal/test.php';
$cancel_url = 'http://domain.co.uk/paypal/payment-cancelled';
$notify_url = 'http:/domain.co.uk/paypal/test.php';
$item_name = 'Item Name';
$item_amount = 1.00;
$invoice = $_POST['invoice'];
// Include Functions
include("functions.php");
// Check if paypal request or response
if (!isset($_POST["txn_id"]) && !isset($_POST["txn_type"])){
$querystring = '';
// Firstly Append paypal account to querystring
$querystring .= "?business=".urlencode($paypal_email)."&";
// Append amount& currency (£) to quersytring so it cannot be edited in html
//The item name and amount can be brought in dynamically by querying the $_POST['item_number'] variable.
$querystring .= "item_name=".urlencode($item_name)."&";
$querystring .= "amount=".urlencode($item_amount)."&";
$querystring .= "invoice=".urlencode($invoice)."&";
//loop for posted values and append to querystring
foreach($_POST as $key => $value){
$value = urlencode(stripslashes($value));
$querystring .= "$key=$value&";
}
// Append paypal return addresses
$querystring .= "return=".urlencode(stripslashes($return_url))."&";
$querystring .= "cancel_return=".urlencode(stripslashes($cancel_url))."&";
$querystring .= "notify_url=".urlencode($notify_url);
// Append querystring with custom field
//$querystring .= "&custom=".USERID;
// Redirect to paypal IPN
header('location:https://www.paypal.com/cgi-bin/webscr'.$querystring);
exit();
} else {
//Database Connection
$link = mysql_connect($servername, $username, $password);
mysql_select_db($db_name);
// Response from Paypal
// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';
foreach ($_POST as $key => $value) {
$value = urlencode(stripslashes($value));
$value = preg_replace('/(.*[^%^0^D])(%0A)(.*)/i','${1}%0D%0A${3}',$value);// IPN fix
$req .= "&$key=$value";
}
// assign posted variables to local variables
$data['item_name'] = $_POST['item_name'];
$data['item_number'] = $_POST['item_number'];
$data['payment_status'] = $_POST['payment_status'];
$data['payment_amount'] = $_POST['mc_gross'];
$data['payment_currency'] = $_POST['mc_currency'];
$data['txn_id'] = $_POST['txn_id'];
$data['receiver_email'] = $_POST['receiver_email'];
$data['payer_email'] = $_POST['payer_email'];
$data['custom'] = $_POST['custom'];
// post back to PayPal system to validate
$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 ('ssl://www.paypal.com', 443, $errno, $errstr, 30);
if (!$fp) {
// HTTP ERROR
} else {
fputs($fp, $header . $req);
while (!feof($fp)) {
$res = fgets ($fp, 1024);
if (strcmp($res, "VERIFIED") == 0) {
// Used for debugging
// mail('user#domain.com', 'PAYPAL POST - VERIFIED RESPONSE', print_r($post, true));
// Validate payment (Check unique txnid & correct price)
$valid_txnid = check_txnid($data['txn_id']);
$valid_price = check_price($data['payment_amount'], $data['item_number']);
// PAYMENT VALIDATED & VERIFIED!
if ($valid_txnid && $valid_price) {
$orderid = updatePayments($data);
if ($orderid) {
// Payment has been made & successfully inserted into the Database
mail("email#email.com","Success","Payment made successfully");
echo "updated";
} else {
// Error inserting into DB
// E-mail admin or alert user
mail('email#email.com', 'PAYPAL POST - INSERT INTO DB WENT WRONG', print_r($data, true));
}
} else {
// Payment made but data has been changed
// E-mail admin or alert user
}
} else if (strcmp ($res, "INVALID") == 0) {
// PAYMENT INVALID & INVESTIGATE MANUALY!
// E-mail admin or alert user
// Used for debugging
//#mail("user#domain.com", "PAYPAL DEBUGGING", "Invalid Response<br />data = <pre>".print_r($post, true)."</pre>");
}
}
fclose ($fp);
}
}
?>
This code handles the response from paypal:
<?php
// STEP 1: read POST data
// Reading POSTed data directly from $_POST causes serialization issues with array data in the POST.
// Instead, read raw POST data from the input stream.
$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 IPN message sent from PayPal and prepend 'cmd=_notify-validate'
$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";
}
// Step 2: POST IPN data back to PayPal to validate
$ch = curl_init('https://www.paypal.com/cgi-bin/webscr');
curl_setopt($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);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
// In wamp-like environments that do not come bundled with root authority certificates,
// please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set
// the directory path of the certificate as shown below:
// curl_setopt($ch, CURLOPT_CAINFO, dirname(__FILE__) . '/cacert.pem');
if ( !($res = curl_exec($ch)) ) {
// error_log("Got " . curl_error($ch) . " when processing IPN data");
curl_close($ch);
exit;
}
curl_close($ch);
// inspect IPN validation result and act accordingly
if (strcmp ($res, "VERIFIED") == 0) {
// The IPN is verified, process it
} else if (strcmp ($res, "INVALID") == 0) {
// IPN invalid, log for manual investigation
}
// inspect IPN validation result and act accordingly
if (strcmp ($res, "VERIFIED") == 0) {
// The IPN is verified, process it:
// check whether the payment_status is Completed
// check that txn_id has not been previously processed
// check that receiver_email is your Primary PayPal email
// check that payment_amount/payment_currency are correct
// process the notification
// 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'];
$invoice = $_POST['invoice'];
// IPN message values depend upon the type of notification sent.
// To loop through the &_POST array and print the NV pairs to the screen:
foreach($_POST as $key => $value) {
echo $key . " = " . $value . "<br>";
}
echo $res;
} else if (strcmp ($res, "INVALID") == 0) {
// IPN invalid, log for manual investigation
echo "Error! Paypal stated payment as: <b>" .$res ."<br />";
}
?>