11:18:12,992 AM [testsystem-pekko.actor.default-dispatcher-7] [INFO] RepointableActorRef -  pekkoDeadLetter Message [java.lang.String] from Actor[pekko://testsystem/system/testActor-13#-454167076] to Actor[pekko://testsystem/user/pingpongactor#1106720216] was not delivered. [1] dead letters encountered. If this is not an expected behavior then Actor[pekko://testsystem/user/pingpongactor#1106720216] 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'.
11:18:12,993 AM [testsystem-pekko.actor.default-dispatcher-7] [INFO] CoordinatedShutdown - Running CoordinatedShutdown with reason [ActorSystemTerminateReason]