How to solve Notice: Trying to get property of non-object (Caused by table altering)

Question

I need to ask this question and I know this might get mark as duplicate since so many people already ask the similar questions but I have read through them and find no answers or similarities to the problem that I'm facing.

Trying to get property of non-object

Okay, right now, I have a table that will show the list of a user for admin to add, edit or delete the user. My problem right now is, the table can only display the users list and when I add the edit and delete part, the notice pops up.

This is my code before alteration of edit and delete;

<?php
$db_host = 'localhost'; // Server Name
$db_user = 'root'; // Username
$db_pass = ''; // Password
$db_name = 'register'; // Database Name

$conn = mysqli_connect($db_host, $db_user, $db_pass, $db_name);
if (!$conn) {
 die ('Failed to connect to MySQL: ' . mysqli_connect_error()); 
}

$sql = 'SELECT * 
  FROM users';
  
$query = mysqli_query($conn, $sql);

if (!$query) {
 die ('SQL Error: ' . mysqli_error($conn));
}
?>
  
 <table class="data-table">
  <caption class="title">List of Users </caption>
  <thead>
   <tr>
   
    <th>USERNAME</th>
    <th>PASSWORD</th>
    <th></th>
    <th></th>
   </tr>
  </thead>
  <tbody>
  
  <?php
  $no  = 1;
  $total  = 0;
  while ($row = mysqli_fetch_array($query))
  {
   echo '<tr>
     <td>'.$row['username'].'</td>
     <td>'.$row['password'].'</td>
    </tr>';
 
  }?>
  </tbody>
 </table> 

and here is my code after the alteration

<?php
$db_host = 'localhost'; // Server Name
$db_user = 'root'; // Username
$db_pass = ''; // Password
$db_name = 'register'; // Database Name

$conn = mysqli_connect($db_host, $db_user, $db_pass, $db_name);
if (!$conn) {
 die ('Failed to connect to MySQL: ' . mysqli_connect_error()); 
}

$sql = 'SELECT * 
  FROM users';
  
$query = mysqli_query($conn, $sql);

if (!$query) {
 die ('SQL Error: ' . mysqli_error($conn));
}
?>
  
 <table class="data-table">
  <caption class="title">List of Users </caption>
  <thead>
   <tr>
   
    <th>USERNAME</th>
    <th>PASSWORD</th>
    <th></th>
    <th></th>
   </tr>
  </thead>
  <tbody>
  
  <?php
  $no  = 1;
  $total  = 0;
  while ($row = mysqli_fetch_array($query))
  {
echo "<tr>";

echo "<td>" . $row->username . "</td>";
echo "<td>" . $row->password . "</td>";
echo "<td><a href='records.php?id=" . $row->id . "'>Edit</a></td>";
echo "<td><a href='delete.php?id=" . $row->id . "'>Delete</a></td>";
echo "</tr>";
 
  }?>
  </tbody>
 </table> 
  
</div>

</body>

Where did I do wrong and how can I solve my problem? Every suggestion and hints are greatly appreciated and please don't mark my question since I believe that my question is totally different from the others.