Double-check the coupon's expiration date and scope of application to ensure it complies with the usage rules. Expired coupons or those not applicable to the purchase will not work. Contact the website's customer service to verify the coupon code's validity. The website may have changed or canceled some promotions. Ensure the coupon code is entered correctly, including any special characters or spaces. Try using a different browser or clearing the cache and cookies, as technical issues can sometimes interfere with coupon application. If the coupon was found through a third-party site, verify its authenticity and check for any restrictions that might apply.
