Please follow the following steps to troubleshoot:
# Whether the total amount of the product is 0
The system has restrictions. If the total amount of the order is 0, the coupon cannot be used.
# Check coupon status
Check out the following elements of this coupon:
+ Check the status to see if it is available. Some users have already used their coupons and still want to use them;
+ Check the validity period of the coupon, the start time to the end time, and whether it meets the conditions for use;
+ Starting amount. Some coupons will set a certain amount of the order before they can be used. If they cannot be used, there is a high probability that this condition is not met;
# Check who can use the coupon
Edit the coupon rules and review and confirm the following elements:
+ For the store it belongs to, if the coupon is specified to be used in a certain store, then if the product ordered is not from this store, it cannot be used;
+ Usage objects, if you specify the category of use of the coupon, or the use of products, then it can only be used under these categories and products. If your order contains other categories or is not the product specified here, then it cannot be used;
# The product settings do not allow the use of coupons
Please confirm the maximum number of coupons allowed for this product set here. If it is set to 0, then this product does not allow the use of coupons.