Could not resolve all files for configuration ':app:debugCompileClasspath'.ソリューション

例外は次のとおりです.

Error:FAILURE: Build failed with an exception.

* What went wrong:
Could not resolve all files for configuration ':app:debugCompileClasspath'.
> Could not resolve com.google.android.gms:play-services-ads:latest.release.
  Required by:
      project :app
   > Could not resolve com.google.android.gms:play-services-ads:12.0.1.
      > Could not get resource 'https://jcenter.bintray.com/com/google/android/gms/play-services-ads/12.0.1/play-services-ads-12.0.1.pom'.
         > Could not GET 'https://jcenter.bintray.com/com/google/android/gms/play-services-ads/12.0.1/play-services-ads-12.0.1.pom'.
            > Read timed out

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 35s

ソリューションは、プロジェクトレベルでのbuild.gradleファイルに次のコードを追加します.

buildscript {

    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.1' //        ，             
        classpath 'com.google.gms:google-services:4.0.1'  //            

    }
}

allprojects {
    repositories {
        google()
        jcenter()
        mavenCentral ()
        maven {url 'https://dl.bintray.com/jetbrains/anko'} //        ，              ，       maven          
        maven {url "https://maven.google.com"} //    
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}