POST到PHP文件时出现500服务器错误

So, I'm trying to work with a simple API parse, POST the data to a PHP file to save into a database. My problem is there is a 500 server error surrounding the POST and I'm not sure what is going on.

Failed to load resource: the server responded with a status of 500 (Internal Server Error)

Here is view-deals.html, this file is where I grab data from API result:

<!DOCTYPE html>
<html>
    <head>
        <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.0/jquery.min.js"></script>
        <?php
            require_once 'db_config.php';
            echo "vd-1";
            //mysql_query($sqlApiAccess) or die('Error, insert query failed');
        ?>
        <script type='text/javascript'>
            $(function () {
                var summonerId = '----------';
                $.getJSON("----------" + ---------- + "/----------?", 
                {
                    api_key: "----------"
                }).done(function (data) {
                    console.log(data);
                    // do whatever processing you need to do to the data

                    $.post('save-deals.php', {dealData: data}, function(finishData) {
                         //This is an optional function for when it has finished saving
                    });

                    // Your formatting comes next
                });
            });
        </script>
    </head>
    <body>
    </body>
</html>

Here is the save-deals.php file where I'm POSTing the data to, to save in the DB:

<!DOCTYPE html>
<html>
   <!--<head>
      <?php
         require_once 'db_config.php';
         //mysql_query($sqlApiAccess) or die('Error, insert query failed');
      ?>
   </head>-->
   <body>
      <?php
         require_once 'db_config.php';
         ob_start(); //I like output-buffering because if we need to change headers mid script nothing dies

         $DealData = isset($_POST['dealData']) ? $_POST['dealData'] : die("Malformed form data!");

         if ($DealData!='') {
            $DealData = $DB->real_escape_string($DealData); //Sanitize it for MySQL

            if (!$DB->query("INSERT INTO deals(data) VALUES ($DealData)") {
               echo "Insert failed: (" . $DB->errno . ") " . $DB->error;
            } else {
               //AT THIS POINT IT SHOULD HAVE BEEN INSERTED!
               //You could return a success string, or whatever you want now.
            }
         } else {
            http_response_code("400");
            die("Bad Request, please check your entry and try again");
         }
         ob_end_flush(); //Close up the output-buffer

      ?>
   </body>
</html>

Here is the network result on view-deals.html page:

enter image description here

Here is the error on save-deals.php page:

enter image description here