Check the fine print for any exclusions or restrictions on the coupon code. Ensure the code hasn't expired and that it applies to the items in your cart. Try a different web browser or device to see if the code works there. Disable browser extensions temporarily as they might interfere with the code. Clear cookies and site data in your browser settings. Use incognito or private browsing mode. Contact customer service for assistance. Search for a new working promo code if the current one is invalid.
