Lots of Google Apps for Education features, products, and extensions need access to the Google and Google+ APIs in order to work — including GoGuardian Director! These APIs allow GoGuardian to understand where students belong in your OU structure.
To enable the Google API:
In the Google Apps Admin Console Dashboard go to Security > API Reference > API Access > Enable API Access
To enable Google+ API Access:
Go to the Google Admin console at admin.google.com.
Click on Apps.
Click on Additional Google Services.
Click on Google+.
Click on Advanced Settings.
Scroll to the bottom of the page, and find Google+ APIs.