I am learning Android apps development. when opening the Android Studio(Version 2.1.2) i get the below error in Gradle Build:

Error:A problem occurred configuring project ':app'.
> Could not download junit.jar (junit:junit:4.12)
> Failed to download resource 'https://jcenter.bintray.com/junit/junit/4.12/junit-4.12.jar'.
> java.lang.NullPointerException (no error message)

Please help!!