Why can't I use the coupon for ordering?

Below are the reasons why you might not be able to apply a discount or coupon code to your order:

a. Only one coupon is allowed per order;
b. The coupon has expired;
c. The coupon is not applicable to the product(s) you selected;
d. The product is already on sale and cannot be combined with a coupon;
e. Discounts do not apply to taxes, price differences, shipping fees, or handling charges.