>>273576826
It's probably a dodgy connection, either on the PC end or the Quest end, movement could be making it disconnect. Could be a little break somewhere inside the cable itself too. 

What you should do first is try another cable and another USB3 or USB3.1 socket on your PC.

Oh and also, if you get it working, see about securing the cable on the Quest end with a piece of velcro or something, just to take strain off the socket.