我有一个用例，其中有一个参与者层次结构

parent -> childABC -> workerchild

现在，worker child开始工作，并将其结果发送给其父项（childABC，即parent的子项），该子执行元（childABC）将结果发送回父执行元。我使用pipeTo并得到死信，这是我的代码
parent演员：

final case object GetFinalValue

class MyActor extends Actor{
  import context.dispatcher
  import akka.pattern.pipe
  val log = LoggerFactory.getLogger(this.getClass)
  val myManageActor = context.actorOf(Props[ManagerMyActor],"Managemyactor")
  implicit val timeout = Timeout(ReadTimeIntervalValue.getInterval(), SECONDS)

  override def receive: Receive = {
    case GetFinalValue=>
      ask(myManageActor,GetValue).pipeTo(sender())

    case message =>
      log.warn(" Unhandled message received : {}", message)
      unhandled(message)
  }

}

childABC（根据上面给出实施例I）

final case object GetValue

class ManagerMyActor extends Actor{
  import context.dispatcher
  import akka.pattern.pipe
  val log = LoggerFactory.getLogger(this.getClass)
  val myTokenActor = context.actorOf(Props[TokenMyActor2],"toknMyActor2")
  implicit val timeout = Timeout(ReadTimeIntervalValue.getInterval(), SECONDS)

  override def receive: Receive = {
    case GetValue=>
      ask(myTokenActor,CalculateValue).pipeTo(sender())

    case message =>
      log.warn(" Unhandled message received : {}", message)
      unhandled(message)
  }

}

child执行元：

final case object CalculateValue

class TokenMyActor2 extends Actor{
  import context.dispatcher
  import akka.pattern.pipe
  val log = LoggerFactory.getLogger(this.getClass)

  override def receive: Receive = {
    case CalculateValue=>
      val future = Future{ "get the string"
      }
      val bac = future.map{result =>
          sender ! result
      }//.pipeTo(sender())

    case message =>
      log.warn("Actor MyActor: Unhandled message received : {}", message)
      unhandled(message)
  }

}

def main(args: Array[String]): Unit = {
    implicit val timeout = Timeout(ReadTimeIntervalValue.getInterval(), SECONDS)

    val myActor = system.actorOf(Props[MyActor],"myActor")
    val future = ask(myActor, GetFinalValue).mapTo[String]
    future.map {str =>
      log.info ("string is {}",str)
    }

以下是日志：

[INFO] [akkaDeadLetter][01/12/2021 19:17:22.000] [api-akka.actor.default-dispatcher-5] [akka://api/deadLetters] Message [java.lang.String] from Actor[akka://api/user/myActor/Managemyactor/toknMyActor2#1239397461] to Actor[akka://api/deadLetters] was not delivered. [1] dead letters encountered. If this is not an expected behavior then Actor[akka://api/deadLetters] 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'.
[INFO] [akkaDeadLetter][01/12/2021 19:17:41.989] [api-akka.actor.default-dispatcher-7] [akka://api/deadLetters] Message [akka.actor.Status$Failure] from Actor[akka://api/user/myActor#1829301550] to Actor[akka://api/deadLetters] was not delivered. [2] dead letters encountered. If this is not an expected behavior then Actor[akka://api/deadLetters] may have terminated unexpectedly. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
[INFO] [akkaDeadLetter][01/12/2021 19:17:41.996] [api-akka.actor.default-dispatcher-7] [akka://api/deadLetters] Message [akka.actor.Status$Failure] from Actor[akka://api/user/myActor/Managemyactor#-269929265] to Actor[akka://api/deadLetters] was not delivered. [3] dead letters encountered. If this is not an expected behavior then Actor[akka://api/deadLetters] 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'.

请告诉我我哪里错了，或者pipeTo不应该这样使用？如果是这样的话，我应该怎么做才能使它工作