10:46:50,929 AM [testsystem-akka.actor.default-dispatcher-5] [INFO] Slf4jLogger - Slf4jLogger started 10:46:51,223 AM [testsystem-akka.actor.default-dispatcher-7] [INFO] RepointableActorRef - Message [java.lang.String] from Actor[akka://testsystem/system/testActor-1#-950328070] to Actor[akka://testsystem/user/pingpongactor#1462209942] was not delivered. [1] dead letters encountered. If this is not an expected behavior then Actor[akka://testsystem/user/pingpongactor#1462209942] 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'.