Firstly check that the watch is charging when you have it plugged in. Press the Power on button once to light up the screen and you should see the battery charging symbol. This is to ensure there is no problem with the charging cable or the socket you have it plugged into.
Next hold the Power on button for about 10 seconds to see if the watch will power on.
Inspect the charging cable to ensure there is no damage to the charging cable.
Try charging the watch using a different socket or test the socket you are using with another appliance to confirm the socket is working correctly
Check if there any sign of damage to the watch.
Please contact firstname.lastname@example.org with the results of the above checks so we may assist you promptly.