Personal Lightroom plan / "Access denied"

I purchased a private Lightroom & Photoshop plan.

Upon trying to open the Lightroom desktop app (for Mac), I am getting the "access denied" error message (attached). Signing in with my Adobe CC ID (which I use on my phone for mobile apps) does not help. 

It's my personal laptop, so I possess all admin rights. 

Restarting the device, and even re-installing the Lightroom deskptop app, did not solve the issue.