Double-check the coupon's expiration date, scope of application, and other restrictions to ensure it complies with the usage rules. Expired or inapplicable coupons will not be accepted. Contact the website's customer service to verify the coupon code's validity. The website may have changed or canceled some promotions, and the code might be from old data. Ensure the website is compatible with the coupon function, as some websites may have integration issues. If the problem persists, report the issue to the relevant support team.
