Android phone connected to webcam but computer screen is black.

I'm using an Android phone connected to a USB hub and powering the hub. I've then connected a webcam to the hub. My computer shows the webcam is there, but the screen is black. How can I fix this?

#2

It usually does that if the resolution is too high so it cannot send data fast enough. Can you turn down the resolution of the camera to the minimum. If that works then slowly turn up the resolution to higher values.