woocommerce pay page and order receive page has 404 error

My woocommerce has a weird problems. I have done any change, but the page with [woocommerce_pay] and the page with [woocommerce_thankyou] has 404 error. The common point for these two page is they both have the parent checkout. However, the checkout page works good. I have tried restore to old backup by ftp. The problem is still there. I have tried to update the woocommerce. The problem hasn`t been solved either.