@warstadt Hello and thank you for your response ??
I use last version of Woocommerce : 3.3.3
In fact I can’t verify if coupon code works because I simply can’t fill field. My problem is that when I clic on “click here to add a coupon code” on the checkout page, the field+button Apply don’t unfold. Normally when we clicK on it, the field to type the code and the button Apply should unfold and be visible (sorry for my english, I hope you understand what I mean).
I see that .checkout_coupon is always on “Display: none;” even if I clic on “Click here to add a coupon code”
As you suggest, I tried to disable all other plugins, and found which plugin is in conflict with woocommerce. This is Woocommerce Poor Guys Swiss Knife.
Should Woocommerce dev team can do somthing or do I have to see with the other plugin ? And you do you use it ? Do you see what could be wrong ?
Thank you