ExecutorMonitor$Tracker NullPointerException

19/08/21 06:44:01 ERROR AsyncEventQueue: Listener ExecutorMonitor threw an exception
java.lang.NullPointerException
	at org.apache.spark.scheduler.dynalloc.ExecutorMonitor$Tracker.removeShuffle(ExecutorMonitor.scala:479)
	at org.apache.spark.scheduler.dynalloc.ExecutorMonitor.$anonfun$cleanupShuffle$2(ExecutorMonitor.scala:408)
	at org.apache.spark.scheduler.dynalloc.ExecutorMonitor.$anonfun$cleanupShuffle$2$adapted(ExecutorMonitor.scala:407)
	at scala.collection.Iterator.foreach(Iterator.scala:941)
	at scala.collection.Iterator.foreach$(Iterator.scala:941)
	at scala.collection.AbstractIterator.foreach(Iterator.scala:1429)
	at scala.collection.IterableLike.foreach(IterableLike.scala:74)
	at scala.collection.IterableLike.foreach$(IterableLike.scala:73)
	at scala.collection.AbstractIterable.foreach(Iterable.scala:56)
	at org.apache.spark.scheduler.dynalloc.ExecutorMonitor.cleanupShuffle(ExecutorMonitor.scala:407)
	at org.apache.spark.scheduler.dynalloc.ExecutorMonitor.onOtherEvent(ExecutorMonitor.scala:351)
	at org.apache.spark.scheduler.SparkListenerBus.doPostEvent(SparkListenerBus.scala:82)
	at org.apache.spark.scheduler.SparkListenerBus.doPostEvent$(SparkListenerBus.scala:28)
	at org.apache.spark.scheduler.AsyncEventQueue.doPostEvent(AsyncEventQueue.scala:37)
	at org.apache.spark.scheduler.AsyncEventQueue.doPostEvent(AsyncEventQueue.scala:37)
	at org.apache.spark.util.ListenerBus.postToAll(ListenerBus.scala:99)
	at org.apache.spark.util.ListenerBus.postToAll$(ListenerBus.scala:84)
	at org.apache.spark.scheduler.AsyncEventQueue.super$postToAll(AsyncEventQueue.scala:102)
	at org.apache.spark.scheduler.AsyncEventQueue.$anonfun$dispatch$1(AsyncEventQueue.scala:102)
	at scala.runtime.java8.JFunction0$mcJ$sp.apply(JFunction0$mcJ$sp.java:23)
	at scala.util.DynamicVariable.withValue(DynamicVariable.scala:62)
	at org.apache.spark.scheduler.AsyncEventQueue.org$apache$spark$scheduler$AsyncEventQueue$$dispatch(AsyncEventQueue.scala:97)
	at org.apache.spark.scheduler.AsyncEventQueue$$anon$2.$anonfun$run$1(AsyncEventQueue.scala:93)
	at org.apache.spark.util.Utils$.tryOrStopSparkContext(Utils.scala:1319)
	at org.apache.spark.scheduler.AsyncEventQueue$$anon$2.run(AsyncEventQueue.scala:93)