Cannot recieve feedback from iOS Push Notification using PHP - php

Question

I have set up a php file on my own server and used it to send push notifications. I have already tried it with two devices and it works well. The problem is with the feedback method which returns nothing. I have already tried everything and disabled firewall and so on. Note that i tested the feedback like this: I run the app on both devices. They both get the notification. then i delete the app on one of them and try again. Here is the PHP code i used:
<?php
$deviceToken1 = '.....';
$deviceToken2 = '.....';
$tokenArr = array($deviceToken1,$deviceToken2);
$passphrase = '.....';
$message = $_POST['message'];
$newsID = $_POST['newsID'];
$ctx = stream_context_create();
stream_context_set_option($ctx, 'ssl', 'local_cert', 'ck.pem');
stream_context_set_option($ctx, 'ssl', 'passphrase', $passphrase);
// Open a connection to the APNS server
$fp = stream_socket_client('ssl://gateway.sandbox.push.apple.com:2195', $err, $errstr, 60, STREAM_CLIENT_CONNECT|STREAM_CLIENT_PERSISTENT, $ctx);
if (!$fp)
exit("Failed to connect: $err $errstr" . PHP_EOL);
echo 'Connected to APNS' . PHP_EOL;
for($i = 0; $i < count($tokenArr); $i++)
{
$body['aps'] = array(
'alert' => $message,
'badge' => 1,
'sound' => 'sound.aiff',
'newsID' => $newsID);
// Encode the payload as JSON
$payload = json_encode($body);
// Build the binary notification
$msg = chr(0) . pack('n', 32) . pack('H*', $tokenArr[$i]) . pack('n', strlen($payload)) . $payload;
// Send it to the server
$result = fwrite($fp, $msg, strlen($msg));
if (!$result) {
echo '<br/>'.date("Y-m-d H:i:s").' Message not delivered' . PHP_EOL;
}
else {
echo '<br/>'.date("Y-m-d H:i:s").' Message successfully delivered' . PHP_EOL;
}
}
stream_context_set_option($ctx, 'ssl', 'local_cert', 'ck.pem');
$apns = stream_socket_client('ssl://feedback.sandbox.push.apple.com:2196', $err, $errstr, 60, STREAM_CLIENT_CONNECT, $ctx);
echo $apns;
if(!$apns)
{
echo '<br/>';
echo "Error $errcode : $errstr\n";
return;
}
else {
echo "APNS feedback results\n";
while ($devcon = fread($fp, 38))
{
$arr = unpack("H*", $devcon);
$rawhex = trim(implode("", $arr));
$feedbackTime = hexdec(substr($rawhex, 0, 8));
$feedbackDate = date('Y-m-d H:i', $feedbackTime);
$feedbackLen = hexdec(substr($rawhex, 8, 4));
$feedbackDeviceToken = substr($rawhex, 12, 64);
echo "TIMESTAMP:" . $feedbackDate . "\n";
echo "DEVICE ID:" . $feedbackDeviceToken. "\n\n";
}
}
?>