Error when accessing Collaborate using a Gmail account: "Access blocked: microsoftonline.com has not completed the Google Verification Process"

Issue

When a client tries to access shared Collaborate folders on the New Collaborate SharePoint site, if logging in using a Googe email account (Gmail) an error similar to the following error appears:

• Access blocked: microsoftonline.com has not completed the Google verification process. The app is currently being tested and can only be accessed by developer-approved testers. 
• Error 403: access_denied

Cause

When enabling Google Federation for the New Collaborate SharePoint site, the Google Project and App that were created has not been published, and have a publishing status of "Testing".

Note: Google has recently made changes to the way apps are accessed, and now requires the app to be verified. 

Solution

You will need to publish the Google Project and App.

Refer to the article Enable Google Federation in Azure for external users with Gmail accounts (following the instructions in Step 2).