if (response.getHttpStatus().orElse(200) == 404) {
                logger.debug("Document not found: url={}", targetUrl);
                saveError(messages -> messages.addErrorsNotFoundOnFileSystem(GLOBAL, targetUrl));
                return redirect(ErrorAction.class);
            }
            return response;
        } catch (final Exception e) {
            logger.warn("Failed to load: {}", doc, e);

     * @param property The property name for the message. (NotNull)
     * @param arg0 The parameter arg0 for message. (NotNull)
     * @return this. (NotNull)
     */
    public FessMessages addErrorsNotFoundOnFileSystem(String property, String arg0) {
        assertPropertyNotNull(property);
        add(property, new UserMessage(ERRORS_not_found_on_file_system, arg0));
        return this;
    }

    /**