Execution failed for task app:transformClassesAndResourcesWithProguardForDebug

when i try to run my app i get these errors: ``` Error:Execution failed for task ':app:transformClassesAndResourcesWithProguardForDebug'. ``` java.io.IOException: Please correct the above warnings first. ``` This is my Gradle file apply plugin: 'com.android.application' android { compileSdkVersion 24 buildToolsVersion "24.0.2" defaultConfig { applicationId "xxxxxxxxxxxxx" minSdkVersion 14 targetSdkVersion 24 versionCode 1 versionName "1.0" } buildTypes { release { minifyEnabled true shrinkResources true proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' } debug { minifyEnabled true shrinkResources true } } } repositories { mavenCentral() } dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) testCompile 'junit:junit:4.12' compile 'com.android.support:appcompat-v7:24.2.1' compile 'com.android.support:design:24.2.1' compile 'com.google.android.gms:play-services:9.8.00' compile 'com.google.android.gms:play-services-auth:9.8.00' compile 'com.facebook.android:facebook-android-sdk:4.0.0' compile 'com.google.android.gms:play-services-ads:9.8.00' compile 'com.firebase:firebase-client-android:2.3.1' compile 'com.google.android.gms:play-services-gcm:9.8.00' } apply plugin: 'com.google.gms.google-services' ``` can any one say why am i getting this error? it shows some jar files are duplicate ,but i dont know which dependency to remove.