From the Knowledge Base

PDF doesn't appear at all - just a link or hangs on 'Loading...'

If the PDF doesn't display at all then please get in touch with our support team via email: Send a link to the page containing the 'broken' embedded PDF. First, you may be able to diagnose the problem yourself

The viewer doesn't display at all (or at wrong size) when inside a Javascript based tab or ajax page transitions

If you attempt to embed the PDF viewer within a tab that is controlled by Javascript, you may find that it does not display at the correct size when the tab is opened. If you resize the browser window slightly,

Error: URL to the PDF file must be on exactly the same domain as the current web page

You will usually see this error in your browser because your PDF does not sit on the same domain as the current page on your site. For example, if you access the page and see the error message: Error: