There are a few reasons this may happen. The most common reason for a coupon error being that the code itself was copied incorrectly. There are a few additional potential causes which are listed below:A different coupon has already been entered. We only accept one coupon per transaction. e.g. If you applied the coupon code for signing up for the HWE Stationery mailing list, you will be unable to enter an additional code. The coupon code expired. If you received the coupon code in your email, please check the expiry date. We normally apply a 30 day expiry for the majority of coupons. (Exceptions to this are: codes associated with our Loyalty Program, codes used for individual customer satisfaction cases, the newsletter signup code, as well as some others)You have already used this coupon code. In most cases, coupon codes are issued at one use per customer.If you are still having issues with your coupon code, please reach out to us at Support@hwestationery.com