10:28:01,887 AM [testsystem-pekko.actor.default-dispatcher-7] [INFO] RepointableActorRef -  pekkoDeadLetter Message [java.lang.String] from Actor[pekko://testsystem/system/testActor-30#1177826069] to Actor[pekko://testsystem/user/pingpongactor#1701584154] was not delivered. [1] dead letters encountered. If this is not an expected behavior then Actor[pekko://testsystem/user/pingpongactor#1701584154] 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'.