If both front and rear LED's are not illuminating, there is an icon in which powers them on and off within the app that may have been hit. Once the board and app are connected together you will see a sun icon beneath the battery percentage bar going across the top.
This sun icon will toggle on and off the lights, the blue color indicates the LEDS should be turned on and you can check to make sure your board shows that is the case. If only one side of the LED's is not illuminating or neither is illuminated and the app shows the blue sun icon, please contact us so we can get that fixed for you!