Adform Close Button

Hi guys,
Does anyone have experience with adding close buttons to adform ads?
I added the close function to a button and somehow it doesn’t work.

dhtml.external.close && dhtml.external.close();

Clicktags are working fine. Am I missing something.
Thanks!

Is there an error in the developer console log?

The main reason that might not work is if you haven’t included the adform dhtml library in the document. Step 5 in this page:

http://support.adform.com/documentation/build-html5-banners/html5-banner-formats/floating-html-ad

If that isn’t the issue, feel free to post a zip of your .hype document.