Thank you for reaching out to us. Sorry for the delay in replying to your support ticket. Please carry out the following troubleshooting steps. Let me know how you go.
I just finish completing a test in my dev site and it works for me. I was able to copy and paste the discount code on the field and then clicked on the Apply button to the right hand side of the field in question. Once I clicked on the Apply button the discount was deducted from the product and displayed before I clicked on the Pay button.
Hi, This is a new item we are trying to introduce to the plugin. We have added some architecture for it but it is not a fully comprehensive feature yet. It has some technical limitations so we can’t make it available for everything.
This is originally not an advertised feature of the plugin. Please assume that this coupon_code option is not working. We will most likely need to roll this back.