Gradle sync failed: Could not resolve all dependencies for configuration ':app:debugRuntimeClasspath'

Question

I recently update my Android Studio to version 3.0.1 and I started a new project with a blank activity. As soon as the gradle sync starts(as soon as I open the project)I get a message in Event Log :

Gradle sync failed: Could not resolve all dependencies for configuration ':app:debugRuntimeClasspath'.
                Could not determine artifacts for com.android.support:appcompat-v7:26.1.0
                Could not get resource 'https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.aar'.
                Could not HEAD 'https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.aar'.
                Connect to dl.google.com:443 [dl.google.com/216.58.197.46] failed: Connection refused: connect
                Connection refused: connect
                Consult IDE log for more details (Help | Show Log) (3s 878ms)

I reinstalled the support repository from Android SDK manager and adding maven to the dependencies but so far have been unable to resolve the issue.

The build-gradle:

// 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:3.0.1'

    // NOTE: Do not place your application dependencies here; they belong
    // in the individual module build.gradle files
 }
}

allprojects {
 repositories {
    google()
    jcenter()
    maven { url "https://maven.google.com" }
    }
}

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

app level build-gradle:

apply plugin: 'com.android.application'

android {
 compileSdkVersion 26
 defaultConfig {
    applicationId "com.example.vishalbisht.test"
    minSdkVersion 15
    targetSdkVersion 26
    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-v7:26.1.0'
 implementation 'com.android.support:design:26.1.0'
 implementation 'com.android.support.constraint:constraint-layout:1.0.2'
 testImplementation 'junit:junit:4.12'
 androidTestImplementation 'com.android.support.test:runner:1.0.1'
 androidTestImplementation 'com.android.support.test.espresso:espresso-
 core:3.0.1'
}

Answer 1

I was able to get around this issue by commenting the following lines in app level build-gradle

   androidTestImplementation 'com.android.support.test:runner:1.0.1'
   androidTestImplementation 'com.android.support.test.espresso:espresso-
   core:3.0.1'

and then it started working not sure if this is an acceptable solution but as of know I can at least run and compile my code.

Also after the Android studio 3.1 update, I have not faced this issue.

Answer 2

Change this

 android {
 compileSdkVersion 26
 defaultConfig {
    applicationId "com.example.vishalbisht.test"
    minSdkVersion 15
    targetSdkVersion 26
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner 
 "android.support.test.runner.AndroidJUnitRunner"
}

To

 android {
 compileSdkVersion 26
 buildToolsVersion '26.0.1'
 defaultConfig {
    applicationId "com.example.vishalbisht.test"
    minSdkVersion 15
    targetSdkVersion 26
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner 
 "android.support.test.runner.AndroidJUnitRunner"
}

And Use any one of this google() or maven { url "https://maven.google.com" }

Read my Previous answer here

Answer 3

Most probably the solution would be as below

1. check target version in your app build.gradle

   targetSdkVersion 30

2. Go to SDK manager and check whether you have the same SDK which should 30 as the API level

Answer 4

upgrade your Gradle and Gradle version plugin to the last version. and migrate your project to androidx.

   classpath 'com.android.tools.build:gradle:3.5.1'

and gradle.wrapper

#Mon Nov 04 15:09:35 IRST 2019
distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-all.zip