Parallel testing using Browserstack.local = true fails

[amarnath-wow]

Executing mvn test -P suite with "browserstack.local": true
fails with java.lan.NullPointerException: null

Terminal error - output
setUp(com.browserstack.suite.SuiteTest09) Time elapsed: 0.005 sec <<< FAILURE!
com.browserstack.local.LocalException: *** Error: Either another browserstack local client is running on your machine or some server is listening on port 45691
at com.browserstack.local.Local.start(Local.java:90)
at com.browserstack.BrowserStackTestNGTest.setUp(BrowserStackTestNGTest.java:64)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.testng.internal.MethodInvocationHelper.invokeMethod(MethodInvocationHelper.java:86)
at org.testng.internal.Invoker.invokeConfigurationMethod(Invoker.java:514)
at org.testng.internal.Invoker.invokeConfigurations(Invoker.java:215)
at org.testng.internal.Invoker.invokeMethod(Invoker.java:589)
at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:820)
at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1128)
at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:129)
at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:112)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)