XF 1.4 iframe a xenforo site

Hi guys!
For some reasons I need to iframe my xenforo site in another webpage, but the page isn't showing up with iframe.

Here is my code:
<!doctype html>
<html lang="zh_CN">
<meta charset="utf-8">
<frameset rows="100%">
<frame src="URL">
<body>Please follow <a href="URL">link</a>!</body>
I'm not sure why this isn't working because it works perfectly with other sites.
Please help! I really need this!