I'm using a one per customer coupon, but in the checkout API if it's already used, the "checkout.applied_discount.non_applicable_reason" just says "discount code isn’t valid for the items in your cart"
The expected result would for it to be the same as in Shopify checkout: "discount code has already been used"
Is there any reason why the API response doesn't use the same language?
There is a specific translation for this, I'm not sure why it isn't being used:
I'm trying to show my customer's a more useful error message. Does anyone know how to do this?