Customizing login error messages

Question

Where and how would I be able to customize the login error messages?

"Error: The username <> is not registered on this site. If you are unsure of your username, try your email address instead."

and "Error: The password you entered for the username <> is incorrect. Lost your password?"

I've tried using this code, but nothing. Any help would be appreciated!

    global $errors;
    $err_codes = $errors->get_error_codes();

    // Invalid username.
    if ( in_array( 'invalid_username', $err_codes ) ) {
        $error = '<strong>ERROR</strong>: This email address is not registered. Please check or contact XXX for more information.';
    }

    // Incorrect password.
    if ( in_array( 'incorrect_password', $err_codes ) ) {
        $error = '<strong>ERROR</strong>: The password you provided is incorrect. Please try again or contact XXX for more information. ';
    }

    return $error;
}

add_filter( 'login_errors', 'my_custom_error_messages');```

Answer 1

I can't see your complete code... However, your code should look like this:

function my_custom_error_messages( $error ) {
    global $errors;
    $err_codes = $errors->get_error_codes();
 
    // Invalid username.
    // Default: '<strong>ERROR</strong>: Invalid username. <a href="%s">Lost your password</a>?'
    if ( in_array( 'invalid_username', $err_codes ) ) {
        $error = '<strong>ERROR</strong>: Wrong username.';
    }
 
    // Incorrect password.
    // Default: '<strong>ERROR</strong>: The password you entered for the username <strong>%1$s</strong> is incorrect. <a href="%2$s">Lost your password</a>?'
    if ( in_array( 'incorrect_password', $err_codes ) ) {
        $error = '<strong>ERROR</strong>: Wrong password.';
    }
 
    return $error;
};
add_filter( 'login_errors', 'my_custom_error_messages' );

The code above has been tested and worked.

Answer 2

In addition to what @Tommy Pradana wrote, here's an array of some of the available error codes you can modify (found in the wp-login.php file):

array( 
    'empty_password',
    'empty_email',
    'invalid_email',
    'invalidcombo',
    'empty_username',
    'invalid_username',
    'incorrect_password',
    'retrieve_password_email_failure' 
);