07:41:40,573 AM [testsystem-akka.actor.default-dispatcher-5] [INFO] Slf4jLogger - Slf4jLogger started
07:41:40,792 AM [testsystem-akka.actor.default-dispatcher-7] [INFO] RepointableActorRef - Message [java.lang.String] from Actor[akka://testsystem/system/testActor-51#1585374926] to Actor[akka://testsystem/user/pingpongactor#9155089] was not delivered. [1] dead letters encountered. If this is not an expected behavior then Actor[akka://testsystem/user/pingpongactor#9155089] may have terminated unexpectedly. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.