AS you all may know from the March 7,2019 google is going to shutdown the support for the Google+ API. This is going to be the progressive shutdown for the Google+ APIs.
So all the calls with the endpoint to the Google+ APIs will start to fail from the January 28,2019.
Google has already started the process of sending an email to their developers/users who are using the Google+ APIs. Even if you didn’t receive that email you must remove the use of that API or switch to some other api calls.
The most commonly used APIs that are being shut down include:
Google+ integration with mobile and web is also going to shutdown.
As a part of the feature Google Sign in feature is available and they are trying to provide a new visual change for the enterprise organizations.
You can find more details on their blog: https://developers.google.com/+/api-shutdown