Android RPC failed

Questions
#1

When I type gradle clean build, it occurrs this.

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微信图片_20190320154205.png1918×570 208 KB

[root@master android_rpc]# gradle clean build --scan

FAILURE: Build failed with an exception.

  • What went wrong:
    A problem occurred configuring root project ‘android_rpc’.

Could not resolve all artifacts for configuration ‘:classpath’.
Could not resolve com.android.tools.build:gradle:3.1.0.
Required by:
project :
Could not resolve com.android.tools.build:gradle:3.1.0.
Could not get resource ‘https://maven.google.com/com/android/tools/build/gradle/3.1.0/gradle-3.1.0.pom’.
Could not GET ‘https://maven.google.com/com/android/tools/build/gradle/3.1.0/gradle-3.1.0.pom’.

#2

seems to be network issue access https://maven.google.com/com/android/tools/build/gradle/3.1.0/gradle-3.1.0.pom