Json Object Runs on localhost but not on Bluehost Server

Question

I have a php script and a jquery script that runs well on localhost (WAMP)but not on my bluehost account.

if i run the same file on live server, the Jquery success function return my json data as null, but not like so on localhost.

below are my codes:

php code:

$transaction_id = trim($_POST['transaction_id']);//get the Transaction ID from Ajax request..

//get the full transaction details as an json from VoguePay
$json = file_get_contents('https://voguepay.com/?v_transaction_id='.$transaction_id.'&type=json');
$transaction=json_decode($json, true);

header('Content-Type: application/json');
echo json_encode($transaction);

The Jquery Section:

            event.preventDefault();
            //clear the display section
            $("#id-input2").html('');
            var data="";
            //call the Ajax Request..
            $.ajax({
                url: "php/fetch_transaction_id.php",
                type: "POST",
                data: {transaction_id:transaction_id},
                dataType: "json",

                beforeSend: function () {
                    $("#transaction_id").attr('disabled', true);
                    $('#searchID').attr('disabled', true);
                    $('#searchID').val('please wait, sending data...');
                },

                success: function (vp_response) {
                    $.map(vp_response, function(index, value) {

                        data=index + ' : ' + value;
                        $("#id-input2").append($("<li>").append(data));
                        $("#id-input2").css('list-style-type', 'none');
                    });


                    $('#searchID').val('Data Received!');
                },

                error: function () {
                    $("#id-input2").append('Sorry, There was an error whilst processing your request');
                    $("#transaction_id").removeAttr('disabled');
                    $("#transaction_id").val('');
                    $("#transaction_id").focus();
                    $('#searchID').removeAttr('disabled');
                    $('#searchID').val('Query Transaction');
                    return false;
                }

            });

Like i said earlier, this file runs on localhost and displays results accordingly. But it doesn't display any data but 'null' on live server.