I have the same issue like PayPal Instant Payment Notification Warning. I have two sites. I have the ipn url set in paypal account to site1. But I'm sending notify_url in paypal form for current site. My verification code on both sites:
public function paymentCheck()
{
$request = 'cmd=_notify-validate';
foreach ($_POST as $key => $value) {
$value = urlencode(stripslashes($value));
$request .= "&$key=$value";
}
$header = "POST /cgi-bin/webscr HTTP/1.1\r\n";
$header .= "Content-Type: application/x-www-form-urlencoded\r\n";
$header .= "Content-Length: " . strlen($request) . "\r\n\r\n";
$fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30);
if (!$fp)
return false;
else {
fputs ($fp, $header . $request);
while (!feof($fp)) {
$res = fgets ($fp, 1024);
if (strcmp ($res, "INVALID") == 0) {
return false;
}
}
fclose ($fp);
}
return true;
}
My sites handle ipn. All working fine. But some of paypal messages is failing and they turned it off. Do you have any ideas, what can cause warnings?