Enter a coupon code
Checkout asked for a coupon but the field was empty (premium.enterCoupon / checkout-coupon).
Why this happens
Client/server validation before lookup. Not “invalid code” yet — nothing was submitted.
Diagnose and fix
1. Type the promo code; apply again.
2. If the field is hidden/disabled, see Coupons are not available.
3. After a code is entered, failures become Coupon code is not valid / apply-failed.
4. Skip coupons and pay full price if optional.