It's most likely a battery problem!
1.
Please make sure the battery is plugged in correctly.
When removing the battery grooves from the instrument - the markings must be mounted facing the top.
2.
If the battery is installed normally, press the power button for more than 2 seconds.
If the battery is plugged in normally but the power does not turn on
Replace it with a new battery (model CR2032).
Nevertheless, if the power does not turn on, please contact us.