在某台电脑连接成功，在笔记本电脑或者另一台电脑却连接失败，板子没有更换过程序，感觉是外部因素，确认了串口没有被占用，连接错误的提示如下
Cannot establelish connection. Please make sure your board is flash with latest firmware and i properly connected with the correct COM port selection and the COM port is not currently in use by other software.
