Signin via Google error

I get the following error while trying to signin via Google.

Unable to sign in. Unexpected error occurred: Legacy People API has not been used in project xxxxxxxxxxxx before or it is disabled. Enable it by visiting https://console.developers.google.com/apis/api/legacypeople.googleapis.com/overview?project=xxxxxxxxxxxx then retry. If you enabled this API recently, wait a few minutes for the action to propagate to our systems and retry.

I have the Google+ API enabled. I am unable to find the Legacy People API in the developers console.

How can this be resolved.