I recommend checking the orientation of the Leap Motion Controller and adjusting this if necessary. To do this, open the Leap Motion Control Panel then go to troubleshooting and open the Diagnostic Visualizer. The cameras should see your hands entering from the bottom of the frame. If this is not the case please change the orientation and save the settings.
If you have any further issues please feel free to email me at firstname.lastname@example.org so I can help further.