macbook adb cannot open interface

Question

I am encountering a problem with Android ADB debugging through USB.

Using Macbook Air 2013 and trying to connect Nexus 6 dev phone.

On the MAC Android Studio

Answer 1

I was debugging my Mobillyo app with a LG K4 phone. I closed Android Studio then enabled USB Debugging in the phone settings,left the settings open, reopened Android Studio did RUN, a dialog opend with the phone info and Unauthorized, was asked to approve on the phone, touched Ok and it worked.