404. That’s an error.
The requested URL /add?feedurl=http://donghovannang-gwinstek.sieuthithietbido.com/dong-ho-van-nang-gw-instek-gdm-350a.rss was not found on this server. That’s all we know.
/add?feedurl=http://donghovannang-gwinstek.sieuthithietbido.com/dong-ho-van-nang-gw-instek-gdm-350a.rss