USB Host port doesn't work

Hi Everyone, I’m new in this world of embedded Linux Software, and I’m learning with my BB Black, but I have a problem

The USB port isn’t recognized, the first time that I plugged the BBB it recognized without any problem, after that I became to using it over Ethernet, powered over USB by an iPhone charger of Apple, and works without any problem.

But now that I want to try the GPIO I plugged to my Mac and it doesn’t recognized. Why? The USER LEDS turn on except the 1, I don’t know why! And I’m desperate! /:

Thank you very much for your help!