OracleJet Grunt Build Fails with Could not resolve com.android.tools.build:gradle:2.1.0.

While doing a grunt build of a oraclejet project in NetBeans, I was getting the below error. To resolve this, added

systemProp.https.proxyHost=<proxy host="">

systemProp.https.proxyPort=<proxy host="" port="">

to gradle.properties in <user home="">/.gradle/ directory

"D:\Program Files\nodejs\grunt.cmd" "oraclejet-build"

Running "oraclejet-build" task

Oracle JET Grunt plugin

Processing Grunt command...

[Warning] Missing platform. Default to android.

Theme Name:Platform - alta:android

Theme Version - 2.1.0

cleaning staging path.....

copy files to staging directory.....

copy finished...

compiling sass....

sass compile skipped...

running theme copy task.....

theme copy finished...

running theme injection task.....

indexHtml theme path injection finished..

injecting index.html with cordova script...

running injection task.....

mainJs paths injection finished..

invoke cordova prepare.....

cordova prepare finished....

invoke cordova compile.....

ANDROID_HOME=D:\android-sdks\sdk

JAVA_HOME=D:\jdk1.7.0_45

Starting a new Gradle Daemon for this build (subsequent builds will be faster).

BUILD FAILED

Total time: 1 mins 26.208 secs

Cordova compile finished....

>> Error: Command failed: C:\windows\system32\cmd.exe /s /c "cordova compile android --debug --emulator"

>> FAILURE: Build failed with an exception.

>> * What went wrong:

>> A problem occurred configuring root project 'android'.

>> > Could not resolve all dependencies for configuration ':classpath'.

>> > Could not resolve com.android.tools.build:gradle:2.1.0.

>> Required by:

>> :android:unspecified

>> > Could not resolve com.android.tools.build:gradle:2.1.0.

>> > Could not get resource 'https://repo1.maven.org/maven2/com/android/tools/build/gradle/2.1.0/gradle-2.1.0.pom'.

>> > Could not GET 'https://repo1.maven.org/maven2/com/android/tools/build/gradle/2.1.0/gradle-2.1.0.pom'.

>> > Connect to repo1.maven.org:443 [repo1.maven.org/151.101.36.209] failed: Connection timed out: connect

>> > Could not resolve com.android.tools.build:gradle:2.1.0.

>> > Could not get resource 'https://jcenter.bintray.com/com/android/tools/build/gradle/2.1.0/gradle-2.1.0.pom'.

>> > Could not GET 'https://jcenter.bintray.com/com/android/tools/build/gradle/2.1.0/gradle-2.1.0.pom'.

>> > Connect to jcenter.bintray.com:443 [jcenter.bintray.com/5.153.35.248] failed: Connection timed out: connect

>> * Try:

>> Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

>> Error: cmd: Command failed with exit code 1 Error output: