So I keep having the same issue. Whenever I download the coupon, it downloads a text file that says “Sorry! Download is not available yet.”
It also isn’t limiting the download to one download per computer.
I am creating the coupons with the Coupon Creator Plugin, which seems to be working great, as I just add in the shortcode. Coupon Creator allows for download as well, but it is still not being limited to one download per computer.