404. That’s an error.
The requested URL /add?feedurl=https://fts-jp.info/index.php%3Fcmd%3Drss%26ver%3D1.0 was not found on this server. That’s all we know.
/add?feedurl=https://fts-jp.info/index.php%3Fcmd%3Drss%26ver%3D1.0