11:12:40,579 AM [testsystem-pekko.actor.default-dispatcher-5] [INFO] Slf4jLogger - Slf4jLogger started 11:12:40,931 AM [testsystem-pekko.actor.default-dispatcher-6] [INFO] CoordinatedShutdown - Running CoordinatedShutdown with reason [ActorSystemTerminateReason] 11:12:40,939 AM [testsystem-pekko.actor.default-dispatcher-5] [INFO] RepointableActorRef - pekkoDeadLetter Message [java.lang.String] from Actor[pekko://testsystem/system/testActor-13#1104301521] to Actor[pekko://testsystem/user/pingpongactor#2122583877] was not delivered. [1] dead letters encountered. If this is not an expected behavior then Actor[pekko://testsystem/user/pingpongactor#2122583877] may have terminated unexpectedly. This logging can be turned off or adjusted with configuration settings 'pekko.log-dead-letters' and 'pekko.log-dead-letters-during-shutdown'.