[Plugin: iframe Shortcode] Doesn't work

Doesn’t work at all here. Instead it’s showing a 404 when in fact the embedded code points to this https://docs.google.com/spreadsheet/embeddedform?formkey=dFJiNjJYbzYyVWlqVUN5cDZhWmdqT0E6MQ.

http://ww.wp.xz.cn/extend/plugins/iframe-shortcode/