Error message not visible

Hello friends,
i have only one little problem,
if i login with correct user and password all is ok,
but if datas are incorrect does not appear any error message.

Some suggestions please?

$redirect = site_url();

			if (isset($_GET['login'])) {

				$login = $_GET['login']; // This variable is used when login failure occurs

				$current_error = $_GET['errcode']; // This variable is used to display the type of error during login

				if ($login == 'failed'){

					if ($current_error == "empty_username" || $current_error == "empty_password"){

						$error_msg = "Enter both Username and Password";

					}

					else if($current_error == 'invalid_username'){

						$error_msg = 'Username is not registered';

					}

					else if($current_error == 'incorrect_password'){

						$error_msg = 'Incorrect Password';

					}

					echo "<div id='message' class='error fade'><p><strong>".$error_msg."</strong></p></div>";

				}

			}

Thanks a lot

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