How to set minimum length and error message for password recovery?

At this moment, my WP site don’t require a minimum length for password recovery, and I want to change that. Since I’m really new at WP plataform, I’ve been searching for a while, and find some methods to add a minimum length here in the Stack Exchange, like this and this. However, this solution worked only parcialy. Am I doing something wrong? I tried to add the following code in wp-login.php and in a custom plugin.

function se_password_min_length_check( $errors, $user){
    if(strlen($_POST['pass1']) < 12)
        $errors->add( 'password_too_short', 'ERROR: password is too short.' 
);
}

add_action( 'validate_password_reset' , 'se_password_min_length_check' 10, 2 
);

With this code, the password isn’t changed with less than 12 chars, but is showing the following error:

Invalid User or Password. To retrieve your password, click here. If necessary, contact us at contact@email.com.

So, my question is: how to change both the minimum length of the password and the error warning when the number of characteres is above the minimum?

I’ve managed to find why I couldn’t change the error message. For some reason, our old dev has put a login_error_override() in Theme’s Function (function.php from theme).

After commented the function call, my custom error worked perfectly, as well the original error messages from theme, wordpress and plugins.

//add_filter('login_errors', 'login_error_override');