| Question | Reason | Solution |
| Driver installation failed | Check whether the corresponding port is generated in the device manager. If the unknow device is displayed, please install the driver manually. | |
| Communication port selection error | Unplug the communication cable and select the correct port | |
| Communication cable failure | (1) Check whether the wiring is correct according to the pin definition. (2) Check whether the communication cable is broken or the pins are loose. (3) Change to a normal communication cable to check. |