if (!fessConfig.isAcceptedSearchReferer(request.getHeader("referer"))) {
            writeJsonResponse(HttpServletResponse.SC_BAD_REQUEST, escapeJsonKeyValue(MESSAGE_FIELD, "Referer is invalid."));
            return;
        }

        if (!fessConfig.isApiSearchScroll()) {
            writeJsonResponse(HttpServletResponse.SC_BAD_REQUEST, escapeJsonKeyValue(MESSAGE_FIELD, "Scroll Search is not available."));

                        }
                        writeJsonResponse(response, HttpServletResponse.SC_NOT_FOUND, createErrorResponse("Session not found"));
                    }
                    return;
                }
                if (logger.isDebugEnabled()) {
                    logger.debug("Message is required but was empty");
                }