Google Apps Directory Sync Administration Guide - Manual (Page 56)

56 Release 4.0.2
Authorizing using OAuth
Click Authorize Now to set up your Authorization settings and create a
verification code.
Note: Customer who already use OAuth will need to authorize again with existing
(or new) credentials. This is because GADS now uses the Directory API instead of
the deprecated Provisioning and Profiles Data APIs, which means the scope for
which the tokens were generated has also changed.
1. Click Sign In to open a browser window and sign in to Google Apps.
2. In the browser page, sign in to Google Apps using administrator credentials.
3. After you enter your credentials, Google Apps automatically displays a token.
Copy that token.
4. Enter the verification code you created in Google Apps in the Verification
Code field.
5. Click Validate to confirm that the code is valid.