There are two apps for authentication with Google accounts:

• Google Authentication is an older app that relies on a system that Google has retired. 
• Google+ Sign-In is the app you should use now.

If you're still using Google Authentication, you should switch over to Google+ Sign-In as soon as possible. The system that the Google Authentication app relied on is no longer supported by Google.

If you are using Deskpro On-Premise, make sure to update your helpdesk to the latest version before installing the Google+ Sign-In app.