I know this is an old thread but stumbled on it while having the issue myself. I found what I believe is the definitive solution. For the Hue Sync App to work on a Mac, you have to grant access in TWO Accessibility areas in the Mac System Preferences...
1) Open System Settings
2) Select "Privacy and Security" (left hand side). Do one, then hit back and do the other:
a) Select "Accessibility" (right hand side. NOT the one on the left!!).
Add/Turn on "Hue Sync" app.
b) Select "Screen Recording" (right hand side).
Add/Turn on "Hue Sync" app.
Why Apple has two things named "Accessibility", and why the Hue website doesn't detail this, well beyond my understanding! But this got it working for me. Hope it helps someone else too