diff --git a/cmd/checkout/pool-server.go b/cmd/checkout/pool-server.go
index 5e17bea..b46ba18 100644
--- a/cmd/checkout/pool-server.go
+++ b/cmd/checkout/pool-server.go
@@ -288,7 +288,7 @@ func (s *CheckoutPoolServer) CreateOrUpdateCheckout(r *http.Request, grain *chec
 	}
 
 	if payment != nil && payment.PaymentId != "" {
-		return s.klarnaClient.UpdateOrder(r.Context(), *grain.OrderId, bytes.NewReader(payload))
+		return s.klarnaClient.UpdateOrder(r.Context(), payment.PaymentId, bytes.NewReader(payload))
 	} else {
 		return s.klarnaClient.CreateOrder(r.Context(), bytes.NewReader(payload))
 	}