try changing the usb cable, and try using it from only the right hand side port on MBP.
I find that my trigger finger will not work on the left hand port of MBP. This is a documented problem. I also had trouble using trigger finger with Imacs, I would have to swap USB ports to get a signal.
When I use it on the right hand side port of my MBP, I have no problems what so ever (sometimes need a rescan midi) Hope this helps.