This may be because of your light being in Travel Lockout Mode.
There are two ways to enter and exit Travel Lock-out Mode for your Gobe.
To enter travel lockout mode, push and hold the power button down for about 5-6 seconds, or until you see the light head momentarily turn on, then off, followed but a red flashing indicator light. Your light should now be locked and unable to turn on in case you place it in a bag and don’t want it to power up, draining your battery.
The second way you can do this is while the light is on. From here, simply push and hold the power button down for about 5-6 seconds. The Light will power down and indicator light will flash red.
To exit travel lockout mode you will follow the same steps as you did to enter it. Hold the power button down for 5-6 seconds until the indication light flashes green, from there you will be able to turn the light on as normal. The Gobe S can also be unlocked by plugging it in to its charger.