Unable to run job server

Beam throws below mentioned error while following the steps to use Spark Portable runner.

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>./learning/katas/java/gradlew :runners:spark:job-server:runShadow{{}}

}}{{Starting a Gradle Daemon (subsequent builds will be faster)
Parallel execution is an incubating feature.FAILURE: Build failed with an exception.

* Where:
Build file '/home/darshan/docker/apache/beam/beam-release-2.18.0/buildSrc/build.gradle' line: 32

* What went wrong:
A problem occurred evaluating project ':buildSrc'.
> Could not find method content() for arguments [build_9gp7982ce87i1sk76auu30fh3$_run_closure1$_closure6$_closure7@26bd394f] on object of type org.gradle.api.internal.artifacts.repositories.DefaultMavenArtifactRepository.* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.* Get more help at https://help.gradle.org
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