There are 3 main reasons a camera will show as disconnected in Social Booth:
1.) Incorrect camera Settings on DSLR models
Ensure that your DSLR camera's 'Auto-off' feature is disabled in the camera menu.
2.) Faulty USB cable
Ensure that the USB cable coming from the camera into the PC or USB hub is not faulty.
Disconnect and reconnect USB cable.
Swap with a new cable.
3.) Faulty USB Hub
Ensure that the USB hub is functioning correctly.
Try swapping ports of USB devices connected to the hub to see if the problem moves.
Ensure that the hub is getting power.
4.) Generic DSLR Power Supply
If you are presented with a battery message on the back of your camera when you power on your photo booth, select "No" when prompted if the battery displays the Canon logo, and select "Yes" when asked if you would like to continue operating the unit (Note: This is a default message. We ship our units with a 'dummy battery' - this is an external power supply, there is no battery present in the actual camera)
Also see video below for proper DSLR Camera settings: