Payment order not found
PayPal confirm (paypal-checkout-confirm) could not find the local payment/order for this capture.
Why this happens
Return URL with a stale/unknown order id, DB row never created, or confirm hit a different environment than checkout start. Distinct from Payment session not found (Stripe session) and Payment not found (admin id).
Diagnose and fix
1. Start checkout again from the site — do not replay an old PayPal return URL.
2. Confirm sandbox/live mode matches PayPal REST credentials.
3. Check that checkout start created a payment row before redirect.
4. See PayPal and Could not create PayPal order — check credentials and sandbox/live mode.