Android Studio Gradle下载失败

在工程主build.gradle下添加阿里云代理

    buildscript {
        repositories {
            maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
        }
    }
 
    allprojects {
        repositories {
            maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
            jcenter()
            maven { url "https://jitpack.io" }
        }
    }