Dji pilot app only compatible with only several android:
-Requires Android 4.1.2 or later.
-Compatible with Samsung S5, Note 3, Sony Xperia Z3, Google Nexus 7 II, Google Nexus 9, Mi 3, Nubia Z7 mini.
(Note: Support for additional devices available as testing and development continues.)
Copy paste from dji official website..
Sorry to say your galaxy note 2 is not supported
Or maybe try to activated your debugging mode (if available on your smartphones)