First get the Configuration File for Sign-in from
Open link below
[https://developers.google.com/identity/sign-in/android/start-integrating][1]
click on get A configuration file
Download the configuration file and place the file in app/ folder of your project
classpath 'com.google.gms:google-services:3.0.0'
apply plugin: 'com.google.gms.google-services'
dependencies { compile 'com.google.android.gms:play-services-auth:9.8.0' }