The file google-sevices.json is missing from module root folder even the file is in the app directory. My gradle version is 2.10. I have spent most of my time to solve this issue but still I cannot resolve the issue.
Project-level gradle
// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.1.0'
        classpath 'com.google.gms:google-services:2.1.0' //this is the latest version
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}
allprojects {
    repositories {
        jcenter()
    }
}
App-Level gradle
apply plugin: 'com.android.application'
android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"
    defaultConfig {
        applicationId "com.myairticket.testpush3"
        minSdkVersion 9
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    sourceSets { main { res.srcDirs = \['src/main/res', 'src/main/jsonfiles'\] } }
}
dependencies {
    compile fileTree(dir: 'libs', include: \['*.jar'\])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.3.0'
    compile 'com.android.support:design:23.3.0'
    compile 'com.google.android.gms:play-services-gcm:8.4.0'
}
apply plugin:'com.google.gms.google-services
 
     
    