Coupon code is required (max 64 characters)
Admin checkout-coupon save rejected: code missing or longer than 64 characters (admin-checkout-coupons).
Why this happens
Empty code field or paste overflow. Not a member-facing apply error.
Diagnose and fix
1. Enter a non-empty code ≤ 64 characters; save again.
2. Avoid spaces-only codes; normalize as the admin UI expects.
3. If creating a duplicate of an existing code, see A coupon with this code already exists.
4. Members applying codes see Coupon code is not valid / enter-coupon prompts instead.