diff --git a/cmd/checkout/adyen-handlers.go b/cmd/checkout/adyen-handlers.go
index 4b17d63..1aac759 100644
--- a/cmd/checkout/adyen-handlers.go
+++ b/cmd/checkout/adyen-handlers.go
@@ -68,6 +68,7 @@ func (s *CheckoutPoolServer) AdyenSessionHandler(w http.ResponseWriter, r *http.
 func getCheckoutIdFromNotificationItem(item webhook.NotificationRequestItem) (uint64, error) {
 	cartId, ok := cart.ParseCartId(item.MerchantReference)
 	if !ok {
+		log.Printf("The notification does not have a valid cartId: %s", item.MerchantReference)
 		return 0, errors.New("invalid cart id")
 	}
 	return uint64(cartId), nil