在我的数据库上更新我的表的状态

i have my codes here, something wrong on my codes, it cant update my table status and req_acknowledge? someone help me. this is what my system run, when i click the button "close" my table status will update to "closed-acknowledged" and when the status is equal to feedback available" and if not, nothing change to the status..

    <?php
            if(isset($_POST['try'])){

$servername = "localhost";
$username = "root";
$password = "";
$dbname = "elev8groupportal";
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

$req_status = mysqli_real_escape_string($conn, $_POST['req_status']);


$sql = "UPDATE request SET req_status='Closed-Acknowledgement', req_acknowledge=NOW() WHERE req_code = '".$_POST['req_code201']."' and req_status= 'Feedback Available'"or die (mysql_error()
 );


if ($conn->query($sql) === TRUE) {
 echo "Record updated successfully";
   

} else {
   echo "Error updating record: " . $conn->error;
}

$conn->close();

}

           ?>  
                <form>
                    Company: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input type="text" value="<?php echo ($dn1['comp_name']); ?>" size="50" readonly></input><br><br>
                    Type of Request: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input type="text" value="<?php echo ($dn1['itrf_type']); ?>" size="50" readonly><br><br>
                    Date Needed: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input type="text" value="<?php echo ($dn1['req_dateneeded']); ?>" size="50" readonly></input><br><br>
                    Project Details: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<textarea name="textarea" rows="2" value=""  cols="50" readonly><?php echo ($dn1['itrf_details']); ?></textarea><br><br>
                     FORM STATUS: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<input type="" value="<?php echo ($dn1['req_status']); ?>" size="50" readonly></input><br><br>
                    _________________________________________________________________________________________________________________
                     <label> Approver Comment:</label><br>
                    <i><textarea rows="3" cols="50" width="100px" id="noter_comment" name="noter_comment" align="right" readonly><?php echo ($dn1['app_comment']); ?></textarea><br /></i>
                      <label> Noter Comment</label><br>
                      <i><textarea rows="3" cols="50" width="100px" id="noter_comment" name="noter_comment" align="right" readonly><?php echo ($dn1['noter_comment']); ?></textarea><br /></i>
                      <label>Request Feedback</label><br>
                      <textarea rows="3" cols="50" width="100px"  id="TRF_comment" name="TRF_comment" align="right" readonly><?php echo ($dn1['TRF_comment']); ?></textarea><br /><br />
                     <button type="submit" class="btn btn-primary" name="try" id="try" >Close Form</button>
                </form> 
               </div>

</div>

I think this can't work:

$sql = "UPDATE request SET req_status='Closed-Acknowledgement', req_acknowledge=NOW() WHERE req_code = '".$_POST['req_code201']."' and req_status= 'Feedback Available'"or die (mysql_error()
 );

remove the ro die bullshit:

$sql = "UPDATE request SET req_status='Closed-Acknowledgement', req_acknowledge=NOW() WHERE req_code = '".$_POST['req_code201']."' and req_status= 'Feedback Available'";