There are several cases where an applied coupon may not work. If the discount or promo code you applied for did not work as expected, check the following:
Some codes have specific terms and conditions such as minimum purchase values, product exclusions, or brand exclusions. Check whether the item(s) in your order meet the eligibility requirements of the coupon you have applied for.
All coupons and promo codes have a start date and an expiry date. Check whether the promotion has started and, more importantly, the expiry date of the coupon you have used.
Manual entry of codes often leads to typing errors. Check to see if you have entered the code correctly. Also check if there is any space before, within, or after the code. There can be no spaces before, within, or after a code. To ensure correct entry, copy and paste the code.
You may not use the same promo or coupon code twice. So, check the terms of your code.