 // MARK: - Private Methods (Last Text Check Timer)
 private extension NicoUtility {
     func setTextSocketEventCheckTimer(delay: Int) {
+        guard isConnected else { return }
         objc_sync_enter(self)
         defer { objc_sync_exit(self) }
         clearTextSocketEventCheckTimer()

        messageSocket = nil

        live = nil
    }

    func startAllTimers() {

        pongCatchTimer?.invalidate()
        pongCatchTimer = nil
        lastPongSocketDates = nil
        log.debug("Stopped ping-pong check timer.")
    }

    @objc func pingPongCheckTimerFired() {
