Coupon does not appear in check out field

-- url of the page with the problem -- : www.urbanoutlet.it/abbigliamento-firmato-siena/
-- HikaShop version -- : 2.3.1
-- Joomla version -- : 2.5.20
-- PHP version -- : 5.4.24
-- Browser(s) name and version -- : Chrome

Hallo. My customer asked me to set up discount coupon on his shop, I created a coupon but it does appear on check out process. I tried to make a buy but the field INSERT COUPON CODE does not appear. Where do I have to set it up in order to make it appear?
I have Hika Essential installed on.

Hi there,

Could you check you have the "coupon" step in your checkout workflow?
You can see that in System>Configuration>Checkout

I did. And now COUPON FIELD appears during checkout. I tried to create a coupon and to insert it in the checkout process but it does not work.
I think I have to set it up correctly.
Any help?

Hello,

I did. And now COUPON FIELD appears during checkout. I tried to create a coupon and to insert it in the checkout process but it does not work.

Coupon code: Fede73

Hi there,

I just tried and it works fine:

Thank you very much!