I am getting NPE error when running testng suite parallel.

[ERROR] [TestNG] TC-99999:java.lang.NullPointerException [runTestListeners::Invoker.java:1883]
java.lang.NullPointerException
at org.jenkinsci.testinprogress.messagesender.MessageSender.println(MessageSender.java:168)
at org.jenkinsci.testinprogress.messagesender.MessageSender.testEnded(MessageSender.java:99)
at com.inMobi.qa.fw.base.reporting.ReportingListener.onTestSuccess(ReportingListener.java:473)
at org.testng.internal.Invoker.runTestListeners(Invoker.java:1887)
at org.testng.internal.Invoker.runTestListeners(Invoker.java:1867)
at org.testng.internal.Invoker.invokeMethod(Invoker.java:775)
at org.testng.internal.Invoker.invokeTestMethod(Invoker.java:894)
at org.testng.internal.Invoker.invokeTestMethods(Invoker.java:1219)
at org.testng.internal.TestMethodWorker.invokeTestMethods(TestMethodWorker.java:127)
at org.testng.internal.TestMethodWorker.run(TestMethodWorker.java:111)
at org.testng.TestRunner.privateRun(TestRunner.java:768)
at org.testng.TestRunner.run(TestRunner.java:617)
at org.testng.SuiteRunner.runTest(SuiteRunner.java:334)
at org.testng.SuiteRunner.access$000(SuiteRunner.java:37)
at org.testng.SuiteRunner$SuiteWorker.run(SuiteRunner.java:368)
at org.testng.internal.thread.ThreadUtil$2.call(ThreadUtil.java:64)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)