Using coupon codes in 3.8.13.3

I have added a coupon code to the designated Coupon area under “Products” section. I’ve tried every different combination but every time I apply the code during checkout to test it, it says “Coupon is not valid.”

Coupon Code – WELCOME10
Discount – 10.00
Discount Type – Percentage
Start and End – N/A
Active – Checked
Use Once – Unchecked
Apply On All Products – Unchecked
Conditions – N/A

I want the coupon available to all products in all categories. No limits, except that it can only be used once.

I am testing on my localserver using WordPress 3.8.1, Storefront Elegance theme 1.5.8 and WP e-Commerce 3.8.13.3.

Any help is greatly appreciated!

https://www.ads-software.com/plugins/wp-e-commerce/