gradle assemble fails for samples

I tried the steps on the home page. But, when I do gradle assemble on a sample after gradle install, I get the following error:

FAILURE: Build failed with an exception.

* Where:
Build file '/home/elrond/Workspace/Other/javafx-gradle/samples/FXML-LoginDemo/build.gradle' line: 1

* What went wrong:
A problem occurred evaluating project ':FXML-LoginDemo'.
> Could not resolve all dependencies for configuration 'classpath'.
   > Could not find org.bitbucket.shemnon.javafxplugin:gradle-javafx-plugin:8.1.0-SNAPSHOT.
     Required by:
         unspecified:unspecified:unspecified

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

server issue. Should work now.