still retry if network failed

    try:

        config = load_config()

        while True:

            try:

                main()

            except RetryError:

                logger.error('Attempts used up. Wait for next %d second', config['interval_check_network'])

            sleep(config['interval_check_network'])

    except BaseHTTPError as err:

        logger.error('{msg}, consider updating \'captive_portal_server\''.format(msg=str(err)))

    except RetryError:

        logger.error('Attempts used up. The program will quit.')

    except Exception as e:

        logger.critical("Critical error occurs", exc_info=True)