title: Gradle project sync failed after finish setting up dependencies for Firebase Authentication
body: <p>By following assistant of Firebase (AndroidStudio: Tool> Firebase), I tried to add Firebase AUthentication to my app.
  But after setting up the dependencies, Gradle project sync failed with error as belows.
  I am struggling to fix this issue...anyone can help me?</p>
  
  <blockquote>
    <p>In project 'app' a resolved Google Play services library dependency
    depends on another at an exact version (e.g. "[15.0. 1]", but isn't
    being resolved to that version. Behavior exhibited by the library will
    be unknown. Dependency failing:
    com.google.android.gms:play-services-flags:15.0.1 ->
    com.google.android.gms:play-services-basement@[
    15.0.1], but play-services-basement version was 16.0.1. The following dependencies are project dependencies that are direct or have
    transitive dependencies that lead to the art ifact with the issue.
    -- Project 'app' depends onto com.google.firebase:firebase-firestore@17.1.4
    -- Project 'app' depends onto com.google.firebase:firebase-database@16.0.5
    -- Project 'app' depends onto com.google.firebase:firebase-auth@16.0.1
    -- Project 'app' depends onto com.firebaseui:firebase-ui-auth@4.1.0 For extended debugging info execute Gradle from the command line with
    ./gradlew --info :app:assembleDebug to see the dep endency paths to
    the artifact. This error message came from the google-services Gradle
    plugin, report issues at https://
    github.com/google/play-services-plugins and disable by adding
    "googleServices { disableVersionCheck = false }" to your b uild.gradle
    file.</p>
  </blockquote>
  
  <h1>Buid.gradle (Project)</h1>
  
  <pre><code>// Top-level build file where you can add configuration options common to all sub-projects/modules.
  
  buildscript {
  
      repositories {
          google()
          jcenter()
      }
      dependencies {
          classpath 'com.android.tools.build:gradle:3.2.1'
          classpath 'com.google.gms:google-services:4.2.0'
  
          // NOTE: Do not place your application dependencies here; they belong
          // in the individual module build.gradle files
      }
  }
  
  allprojects {
      repositories {
          google()
          jcenter()
      }
  }
  
  task clean(type: Delete) {
      delete rootProject.buildDir
  }
  
  // Define versions in a single place
  ext {
      roomVersion = '1.1.1'
      archLifecycleVersion = '1.1.1'
      supportLibraryVersion = '26.1.0'
  }
  </code></pre>
  
  <h1>Biud.gradle (Module)</h1>
  
  <pre><code>apply plugin: 'com.android.application'
  apply plugin: 'com.google.gms.google-services'
  
  android {
      compileSdkVersion 27
      defaultConfig {
          applicationId "com.poc.android.myhospitals"
          minSdkVersion 21
          targetSdkVersion 27
          versionCode 1
          versionName "1.0"
          testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
      }
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
          }
      }
  }
  
  dependencies {
      implementation fileTree(dir: 'libs', include: ['*.jar'])
      implementation 'com.android.support:appcompat-v7:27.1.1'
      implementation 'com.android.support.constraint:constraint-layout:1.1.3'
      implementation 'com.android.support:design:27.1.1'
      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'
      implementation 'com.android.support:recyclerview-v7:27.1.1'
      implementation "com.android.support:support-v4:$rootProject.supportLibraryVersion"
  
      // Firebase
      implementation 'com.google.firebase:firebase-firestore:17.1.4'
      implementation 'com.google.firebase:firebase-database:16.0.5'
      implementation 'com.google.firebase:firebase-auth:16.0.1:15.0.0'
      implementation 'com.firebaseui:firebase-ui-auth:4.1.0'
  
      // Room components
      implementation "android.arch.persistence.room:runtime:$rootProject.roomVersion"
      annotationProcessor "android.arch.persistence.room:compiler:$rootProject.roomVersion"
  
      // Lifecycle components
      implementation "android.arch.lifecycle:extensions:$rootProject.archLifecycleVersion"
      annotationProcessor "android.arch.lifecycle:compiler:$rootProject.archLifecycleVersion"
      implementation "android.arch.lifecycle:viewmodel:1.1.1"
  
      implementation 'com.jakewharton.timber:timber:4.7.1'
  }
  </code></pre>