Check your package name on your google-services.json it should be same with your local package name of your app
Example
"client_info": {
"mobilesdk_app_id": "1:6596814400689:android:65d6f25f5006145",
"android_client_info": {
"package_name": "com.my.app.package.name"
}
In this case my local package name is com.my.app.package.name so also i have changed my package name in google-services.json with my local package name