Double-check the coupon's expiration date and scope of application to ensure it complies with the usage rules. Verify with customer service if the coupon code is valid, as the website may have changed or canceled some promotions. Ensure the coupon code is entered correctly without any typos. Clear browser cookies and cache or try using a different browser. Check for any restrictions on the coupon, such as minimum purchase requirements or specific product exclusions. Try using a different coupon code if available. If the problem persists, contact the website's support team for further assistance.
