My very first reaction to that symptom would be: make sure that the power cable is plugged into the drive. The fact that the little green light comes on suggests that it is, but I'd open it up and unplug/replug both the data and power connections to make sure they're secure just to be on the safe side.
Unplug then replugging and firmly making sure that the SATA power is pluged in solve my problem
. I’ll try to not make that mistake again.