In order to power on and stay on this unit requires secure power and an active data connection to the computer. This means it has to be plugged into a Thunderbolt connection on a computer that is powered on. It will not power on with AC alone.
Secure power just meant it is attached securely and not loose. Sometimes users have them not pressed in all the way.
Do you happen to have another power cord you can try? They are standard universal power cords. Otherwise what you would do at this point is send the unit in for replacement. I suggest calling in to our support to get an RMA setup for the enclosure. (888) 426-5214