Hi mate, no known incompatibilities. Have you got any restrictions set up for the product, or does it require being logged in?

Actually I've just tested your site with JavaScript disabled and the button appears fine, so you have some javascript removing it for some reason.

You could try this fix, which removes one of the css classes, which might be what the script is looking at before removing.

https://wordpress.org/support/topic/my-download-button-does-work/#post-14962128

Nevermind, it appears you have it working again 🙂

I've solved using [download_now_page] shortcode.