update it here,,<br />
<b>Warning</b>:  Cannot modify header information - headers already sent by (output started at /home/khghwvzx/viewmatt.co.ke/callback.php:1) in <b>/home/khghwvzx/viewmatt.co.ke/callback.php</b> on line <b>9</b><br />
<br />
<b>Warning</b>:  http_response_code(): Cannot set response code - headers already sent (output started at /home/khghwvzx/viewmatt.co.ke/callback.php:1) in <b>/home/khghwvzx/viewmatt.co.ke/callback.php</b> on line <b>17</b><br />
{"ResultCode":1,"ResultDesc":"Invalid callback payload"}