There are several reasons why this could happen:
- Lack of power
- Incorrect COM port
- Serial UART device connected to the the programming UART (COM0 of the display)
If upon checking everything above, the display still can't be programmed. It would be best to check the following:
- Is the same PC been used to previously program it?
- Does the PC work for other modules?
- What is the machine/application that this display is installed in?
- What environmental conditions does it experience? (ex. vibrations, humidity, temperature etc.)
After gathering the above information, please contact technical support team by filling up the support form.