Diagnosis
The control box isn't getting enough power. Yeah, this one's common. The power supply or its connection is the usual suspect.
How to Fix It
First, check the physical connections. Unplug the power brick from the wall outlet and from the desk's control box. Check the cable for any kinks or damage. Firmly reconnect everything, making sure the connector clicks into the control box port. Try a different wall outlet that you know works.
If That Didn't Work
Your power supply might be dead. The Fully Jarvis uses a specific 24V DC power adapter. If swapping the connections didn't help, you'll likely need a replacement. Contact Fully support; they can verify and send you the correct part.
Heads Up
Don't try to force the desk manually while it's powered on or trying to move. You can damage the motors. If you need to adjust it to get to connections, unplug it first and then you can carefully lift or lower the top by hand.