HỏiPHP NÀY SAI Ở ĐÂU MÀ KHÔNG XOÁ ĐƯỢC NHỈ ANH EM

<?php
session_start();
if (!isset($_SESSION['username'])) {
header ('Location: /login.html');
exit;
}
require("../system/config.php");
   if(isset($_GET[xoa])){
$idfbxoa = $_GET['xoa'];
$idfbxoa = (int)$idfbxoa;
mysqli_query($conn,"DELETE FROM `idtt` WHERE `idtt`.`id` = '".intval($_GET[xoa])."'");
    echo '<meta http-equiv=refresh content="0; URL=/index.php">';
die('<script>alert("Xóa Thành Công"); </script>');
}
?>
 
 
 
<div class="card">
                            <div class="card-body">
<center><h2>ID TƯƠNG TÁC CỦA BẠN</h2></center><hr/>
                                <div class="table-responsive">
                                    <table id="datatable" class="table table-striped table-bordered dt-responsive nowrap" style="border-collapse: collapse; border-spacing: 0; width: 100%;">
                                        <thead>
                                            <tr>
                                            <th scope="col" width="25px">#</th>
                                            <th scope="col">ID TT</th>
 
<th scope="col">Thời gian thêm</th>
         <th scope="col">Q.Lý</th>                                  
                                            </tr>
                                        </thead>
                                        <tbody>
 
<?php
$lsmua = mysqli_query($conn,"SELECT * FROM idtt WHERE username = '$taikhoan'");
while ($ls = mysqli_fetch_assoc($lsmua)) {
?>                                           <tr>
                                            <td scope="col" width="25px"><?php echo $ls['id'] ?></td>
                                            <td scope="col"><a href="//facebook.com/<?=$ls['idfb'];?>" target="_blank"><?php echo $ls['idfb'] ?></a></td>
 
<td scope="col"><?php echo $ls['date'] ?></td> 
  <td><a href="?xoa=<?php echo $ls['id'] ?>"><button class="btn-sm btn-danger">Xóa</button></a>
</td>                                         </tr>
<?php } ?>
 
 
 
 
                                        </tbody>
                                        </table>
                                </div>
                            </div>
                        </div>
                    </div>

$_GET['xoa']

$_GET[xoa]

WHERE `id`=

WHERE `idtt`.`id`=