XML Parsing Error: no root element found Location: file:///C:/xampp/htdocs/EdgarSerna95_Lab/login.html Line Number 37, Column 3:

XML Parsing Error: no root element found Location: file:///C:/xampp/htdocs/EdgarSerna95_Lab/php/login.phpLine Number 37, Column 3:

<?php
header('Content-type: application/json');

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "jammer";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    header('HTTP/1.1 500 Bad connection to Database');
    die("The server is down, we couldn't establish the DB connection");
}
else {
    $conn ->set_charset('utf8_general_ci');
    $userName = $_POST['username'];
    $userPassword = $_POST['userPassword'];

    $sql = "SELECT username, firstName, lastName FROM users WHERE username = '$userName' AND password = '$userPassword'";
    $result = $conn->query($sql);

    if ($result->num_rows > 0) {
        while($row = $result->fetch_assoc()) {
            $response = array('firstName' => $row['firstNameName'], 'lastName' => $row['lastName']);
        }
        echo json_encode($response);
    }
    else {
        header('HTTP/1.1 406 User not found');
        die("Wrong credentials provided!");
    }
}
$conn->close();
?>

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

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.0/jquery.min.js"></script>
    <form class="modal-content animate" method="post">
    <div class="container">
        <label><b>Username</b></label>
        <input type="text" id="usernameinput" placeholder="Enter username" name="uname" required>
        <label><b>Password</b></label>
        <input type="password" id="passwordinput" placeholder="Enter Password" name="psw" required>
        <button onclick="document.getElementById('id01').style.display='block'">Sign Up</button>
        <button type="button" id="loginsubmit" onclick="myLogin(document.getElementById('usernameinput').value, document.getElementById('passwordinput').value)">Login</button>
    </div>
    </form>

function myLogin(username, password){
var datasend=("user="+username+"&pwd="+password);
$.ajax({
    url: 'makeUserEntry.php',
    type: 'POST',
    data: datasend,
    success: function(response, status) {
        if(response=="Username or Password did not match"){
            alert("Username or Password did not match");
        }
        if(response=="Connection Failure"){
            alert("Connection Failure");
        }
        else{
            localStorage.userid = response;
            window.location.href = "./maze.html"
        }
    },
    error: function(xhr, desc, err) {
        console.log(xhr);
        console.log("Details: " + desc + "nError:" + err);
        var response = xhr.responseText;
        console.log(response);
        var statusMessage = xhr.status + ' ' + xhr.statusText;
        var message  = 'Query failed, php script returned this status: ';
        var message = message + statusMessage + ' response: ' + response;
        alert(message);
    }
}); // end ajax call
}

<?php
$MazeUser=$_POST['user'];
$MazePass=$_POST['pwd'];


//Connect to DB
$servername="127.0.0.1";
$username="root";
$password="password";
$dbname="infinitymaze";
//Create Connection
$conn = new MySQLi($servername, $username, $password, $dbname);
//Check connetion
if ($conn->connect_error){
    die("Connection Failed:  " . $conn->connect_error);
    echo json_encode("Connection Failure");
}
$verifyUPmatchSQL=("SELECT * FROM mazeusers WHERE username LIKE '$MazeUser' and password LIKE '$MazePass'");
$result = $conn->query($verifyUPmatchSQL);
$num_rows = $result->num_rows;
if($num_rows>0){
    $userIDSQL =("SELECT mazeuserid FROM mazeusers WHERE username LIKE '$MazeUser' and password LIKE '$MazePass'");
    $userID = $conn->query($userIDSQL);
    echo json_encode($userID);
}
else{
    echo json_encode("Username or Password did not match");
}

$conn->close();
?>

}