Company Website in IFrame on entity form.

Hi

I have put an Iframe on account entity record and set URL as http://www.cpmpanyname.com in designer. But it is not showing up.  It is showing following error message:

To help protect the security of information you enter into this website, the publisher of this content does not allow it to be displayed in a frame

Any reason why?

I have enabled XSS filter and entered the website into trusted sites.