When the adapter is plugged into a USB port, a green light should come on inside of it which indicates it is being powered. If the light does not come on, remove the adapter from any hub or USB extension cable and plug it directly into a USB port on the computer. If the light come on, it means the hub or extension cord is not supplying power. If the light doesn't come on, please try other ports on the computer.
If none of the ports works, restart the computer and try again. If problem remains, it is likely the adapter is malfunctioning and needs replacement, please contact Avantree. If the light is on when plugged into the second computer, the first computer might have a low-level USB or driver issues.