This coupon does not apply a discount to this plan
Coupon validate/apply returned premium.couponNoDiscount — the code is recognized but does not reduce this plan’s price.
Why this happens
Coupon restricted to other plans/products, zero applicable discount for this price, or misconfigured discount rules. Distinct from Coupon code is not valid (unknown code) and This coupon has expired or is disabled.
Diagnose and fix
1. Try another plan the promo is meant for, or pay without the code.
2. Admin: check coupon plan/product restrictions and discount type/amount.
3. Re-save the coupon if rules were edited incorrectly.
4. See coupon-invalid / already-used siblings.