This checkout session has no payment intent to refund
Admin refund loaded the Stripe Checkout Session but found no payment_intent to refund (400).
Why this happens
Session never completed payment, used a mode without a PI, or externalId points at a session that is not refundable this way. Distinct from Could not load Stripe checkout session for this payment (retrieve failed) and Refunds are only implemented for Stripe payments.
Diagnose and fix
1. Confirm the payment is completed and is a Stripe Checkout charge.
2. In Stripe Dashboard, open the session/payment and verify a PaymentIntent exists.
3. If unpaid/canceled, do not refund — mark locally as needed.
4. See Only completed payments can be refunded.