David Musgrave explores why Security Settings are not working for a Company . Hint, it’s a lot like making sure the computer is plugged in.
Security Settings are not working for a Company – Developing for Dynamics GP – Site Home – MSDN Blogs
Install, Upgrade & AdminMicrosoft & the GP Ecosystem
Archived post from 2012. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.