You have most probably accidentally created a loyalty program coupon code.
If you accidentally created a coupon for a set amount of points and you didn’t end up using this discount because, you didn’t want to or you used another coupon, you can use this coupon later. Your points haven’t been lost and the coupon code is accessible through the Loyalty Program widget.
You can access the Loyalty Program widget in the bottom right on the website (non checkout pages). If you click the widget (while signed in) and then select “See My Rewards (middle right) you can view all the coupons you have created in the past. Just view one and copy the discount code and put it in the discount section on the checkout page.
NOTE: Points discounts can’t be used with other discounts.