Error:Execution failed for task ':app:processDebugGoogleServices'. Android

Question

Error:Execution failed for task ':app:processDebugGoogleServices'. Please fix the version conflict either by updating the version of the google-services plugin (information about the latest version is available at https://bintray.com/android/android-tools/com.google.gms.google-services/) or updating the version of com.google.android.gms to 9.0.2

This is the error I am getting. Below is my gradle file. I have tried many solutions of stackoverflow but none worked in my case.

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.3"

    defaultConfig {
        applicationId "com.radioaudio.motivationalaudios"
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        multiDexEnabled true
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.4.0'
    compile files('libs/YouTubeAndroidPlayerApi.jar')
    compile 'com.google.android.gms:play-services:9.0.2'
    compile 'com.google.firebase:firebase-ads:9.0.2'
    compile 'com.google.firebase:firebase-core:9.0.2'
    compile 'com.android.support:design:23.4.0'
    compile 'com.android.support:multidex:1.0.1'

    compile 'com.onesignal:OneSignal:2.+@aar'
    compile 'com.google.android.gms:play-services-gcm:+'
    compile 'com.google.android.gms:play-services-analytics:+'
    compile 'com.google.android.gms:play-services-location:+'
}
apply plugin: 'com.google.gms.google-services'

Answer 1

compile with

dependencies {
    compile 'com.google.android.gms:play-services:9.6.1'
}

and remove

compile 'com.google.android.gms:play-services-gcm:+'
compile 'com.google.android.gms:play-services-analytics:+'
compile 'com.google.android.gms:play-services-location:+'

apply plugin: 'com.google.gms.google-services'

It should work