404. That’s an error.
The requested URL /add?source=atgs&feedurl=http%3A%2F%2Fmumie0.webnode.ru%2Frss%2Fall.xml was not found on this server. That’s all we know.
/add?source=atgs&feedurl=http%3A%2F%2Fmumie0.webnode.ru%2Frss%2Fall.xml