@VictorW 

Hi,
Please try the following steps if the Tapo C402 can't be powered on.
  1. Charge the battery using the USB cable included in the package. 
  2. Remove the microSD card from the camera if there is one.
  3. Press the power button on the camera for 3 seconds to turn on the camera. 
  4. If the camera still can't be powered on, try connecting the power adapter to another socket.

If the camera has the same behavior, you can contact our support team to check if the camera is under warranty.

Best Regards