title: Flutter problems: "Could not resolve all artifacts for configuration ':classpath' "
body: <p>I am trying to run a flutter app I am writing on my device but when I try to run, I never get past the "assembleDebug" stage and get this message in the terminal:</p>
  
  <pre><code>Launching lib\main.dart on SM N950U in debug mode...
  Running Gradle task 'assembleDebug'...
  
  FAILURE: Build failed with an exception.
  
  * What went wrong:
  A problem occurred configuring root project 'android'.
  &gt; Could not resolve all artifacts for configuration ':classpath'.
     &gt; Could not find com.android.tools.build:gradle:5.6.2.
       Searched in the following locations:
         - https://dl.google.com/dl/android/maven2/com/android/tools/build/gradle/5.6.2/gradle-5.6.2.pom
         - https://dl.google.com/dl/android/maven2/com/android/tools/build/gradle/5.6.2/gradle-5.6.2.jar
         - https://jcenter.bintray.com/com/android/tools/build/gradle/5.6.2/gradle-5.6.2.pom
         - https://jcenter.bintray.com/com/android/tools/build/gradle/5.6.2/gradle-5.6.2.jar
       Required by:
           project :
  
  * 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 14s
  Finished with error: Gradle task assembleDebug failed with exit code 1
  </code></pre>
  
  <p>I have recently updated to gradle 6.0.1 (I assume I did that correctly but I am very new to all this) and there are no issues with flutter doctor.</p>
  
  <p>Here is my project level build.gradle:</p>
  
  <pre><code>buildscript {
      ext.kotlin_version = '1.3.50'
      repositories {
          google()
          jcenter()
      }
  
      dependencies {
          classpath 'com.android.tools.build:gradle:5.6.2'
          classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
          classpath 'com.google.gms:google-services:4.3.3'
      }
  }
  
  allprojects {
      repositories {
          google()
          jcenter()
      }
  }
  
  rootProject.buildDir = '../build'
  subprojects {
      project.buildDir = "${rootProject.buildDir}/${project.name}"
  }
  subprojects {
      project.evaluationDependsOn(':app')
  }
  
  task clean(type: Delete) {
      delete rootProject.buildDir
  }
  </code></pre>
  
  <p>Here is the app level build.gradle:</p>
  
  <pre><code>def localProperties = new Properties()
  def localPropertiesFile = rootProject.file('local.properties')
  if (localPropertiesFile.exists()) {
      localPropertiesFile.withReader('UTF-8') { reader -&gt;
          localProperties.load(reader)
      }
  }
  
  def flutterRoot = localProperties.getProperty('flutter.sdk')
  if (flutterRoot == null) {
      throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
  }
  
  def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
  if (flutterVersionCode == null) {
      flutterVersionCode = '1'
  }
  
  def flutterVersionName = localProperties.getProperty('flutter.versionName')
  if (flutterVersionName == null) {
      flutterVersionName = '1.0'
  }
  
  apply plugin: 'com.android.application'
  apply plugin: 'kotlin-android'
  apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
  
  android {
      compileSdkVersion 28
  
      sourceSets {
          main.java.srcDirs += 'src/main/kotlin'
      }
  
      lintOptions {
          disable 'InvalidPackage'
      }
  
      defaultConfig {
          // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
          applicationId "com.example.skypeclone1"
          minSdkVersion 16
          targetSdkVersion 28
          versionCode flutterVersionCode.toInteger()
          versionName flutterVersionName
          testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
          multiDexEnabled true
      }
  
      buildTypes {
          release {
              // TODO: Add your own signing config for the release build.
              // Signing with the debug keys for now, so `flutter run --release` works.
              signingConfig signingConfigs.debug
          }
      }
  }
  
  flutter {
      source '../..'
  }
  
  dependencies {
      implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
      testImplementation 'junit:junit:4.12'
      androidTestImplementation 'com.android.support.test:runner:1.0.2'
      androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
  }
  apply plugin: 'com.google.gms.google-services'
  </code></pre>
  
  <p>Here are my Gradle wrapper properties in case they are also important.</p>
  
  <pre><code>#Fri Jun 23 08:50:38 CEST 2017
  distributionBase=GRADLE_USER_HOME
  distributionPath=wrapper/dists
  zipStoreBase=GRADLE_USER_HOME
  zipStorePath=wrapper/dists
  distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip
  </code></pre>
  
  <p>gradle.properties</p>
  
  <pre><code>org.gradle.jvmargs=-Xmx1536M
  android.useAndroidX=true
  android.enableJetifier=true
  android.enableR8=true
  </code></pre>