如何在我的PHP网站中修复“欺骗性站点提前”Chrome警告？

Question

以下PHP代码正常运行，但在Chrome中显示“欺骗性网站提前”的警告，如下面的屏幕截图所示。

解决问题需要进行哪些更改？

我在插入数据库之前对密码进行哈希处理。

$_SESSION['message'] = '';
$conn = new mysqli("localhost", "root","", "onlineexam");
if ($conn->connect_error) 
{
    $_SESSION['message'] = "Connection failed: " . $conn->connect_error ;
}
  $_SESSION['message'] = "<span class='alert alert-success'>Database Connection Successful.</span>";


//the form has been submitted with post
if ($_SERVER["REQUEST_METHOD"] == "POST") 
  {

    //two passwords are equal to each other
    if ($_POST['password'] == $_POST['conf_password']) 
    {

        //set all the post variables
        $username = $conn->real_escape_string($_POST['username']);
        $email = $conn->real_escape_string($_POST['email']);
        $user_role = $conn->real_escape_string($_POST['user_role']);
        $password = password_hash($_POST['password'],PASSWORD_DEFAULT); //md5 has password for security

      //Duplicate check username is primary key
                $dupesql = $conn->query("SELECT * FROM users where username = '$username'");
                  $row_cnt = $dupesql->num_rows;
                  if( $row_cnt > 0)
                  {
                      $_SESSION['message']  = "Username is already exist.";

                  }
                else
                {
                    //insert user data into database
                    $sql = "INSERT INTO users (username,email,password,user_role) VALUES ('$username', '$email', '$password','$user_role')";


                    if ($conn->query($sql) == true)
                    {
                        $_SESSION['message'] = "<span class='alert alert-success' style='.body-content{display:none;}'>Registration successful! 
                                                  </span><br/><br/>
                                                  <a href='login.php'>
                                                     <button type='button' class='btn btn-primary' > Login </button>
                                                  </a>";
                    }
                    else {
                    $_SESSION['message'] = 'User could not be added to the database!';
                         }
                } 
    }
    else 
       {
        $_SESSION['message'] = 'Password does not match the confirm password.';
       }
   }