Cursor.LockState = CursorLockMode.Locked doesn‘t works。

i wanted to create a pause menu screen and make it when it is on the cursor lock mode is in none and when the menu is off the cursor is locked, but when i try to lock exiting from the menu it doasnt locks.

here is my code:

 void Update()
     {
         menuTimer = GetComponent<panel_manager>().timer;
         //Debug.Log(menuTimer);
         if (Input.GetKeyDown(KeyCode.Escape) && PauseMenu.active == false && menuTimer == 0)
         {
             Cursor.visible = true;
             Cursor.lockState = CursorLockMode.None;
             Time.timeScale = 0;                             // 暂停
             m_player.enabled = false;
             waterAudio.SetActive(false);
             BGMAudio.GetComponent<AudioSource>().Pause();
             PauseMenu.SetActive(true);
         }
         else if (Input.GetKeyDown(KeyCode.Escape) && PauseMenu.active == true && quitWindow.active == false && menuTimer == 0)
         {
             Cursor.visible = false;
             Cursor.lockState = CursorLockMode.Locked;
             if (Cursor.lockState == CursorLockMode.Locked)
             {
                 Debug.Log("123");
             }
             m_player.enabled = true;
             waterAudio.SetActive(true);
             BGMAudio.GetComponent<AudioSource>().Play();
             Time.timeScale = 1;                             // 继续
             PauseMenu.SetActive(false);
         }

......