With the following function :

function require_login() {
        if ( !is_user_logged_in() ) {
           auth_redirect();
        }
    }

Which action should be used?

add_action('template_redirect', 'require_login');

or

add_action('get_header', 'require_login');

I’ve always used template_redirect in the past but lately it doesn’t seem to always work.