DIAGNOSIS The USB power supply failed, the cable is damaged, or the port on the camera is loose.
FIX First, test with a different, known-good USB power adapter and cable. Use one from a recent phone or tablet (rated 5V/2A). Plug directly into a wall outlet, not a power strip or computer USB port.
IF THAT DIDN'T WORK Inspect the camera's micro-USB port for bent pins or debris. Gently clean it with a dry toothpick. Try wiggling the cable when it's plugged in to see if you get a momentary light—this indicates a broken port.
HEADS UP If the port is damaged, the camera needs repair/replacement. Continuing to force a cable can cause a short. Ring's warranty may cover this if the unit is new.