处理数千个数据时遇到此错误：
[INFO] [01/06/2016 19:04:00.511] [elasticmq-akka.actor.default- dispatcher-4] [akka://elasticmq/deadLetters] Message [scala.collection.immutable.Nil$] from Actor[akka://elasticmq/user/$a/$b#1345840207] to Actor[akka://elasticmq/deadLetters] was not delivered. [1] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
[Fatal Error] :1:1: Content is not allowed in prolog.
| Error 2016-01-06 19:04:00,502 [elasticmq-akka.actor.default-dispatcher-2] ERROR sqs.TheSQSRestServerBuilder$$anon$1 - Exception when running routes
Message: Ask timed out on [Actor[akka://elasticmq/user/$a/$b#1345840207]] after [21000 ms]
Line | Method
->> 334 | apply$mcV$sp in akka.pattern.PromiseActorRef$$anonfun$1
| 117 | run in akka.actor.Scheduler$$anon$7
| 599 | unbatchedExecute in scala.concurrent.Future$InternalCallbackExecutor$
| 109 | execute in scala.concurrent.BatchingExecutor$class
| 597 | execute . . . . in scala.concurrent.Future$InternalCallbackExecutor$
| 467 | executeTask in akka.actor.LightArrayRevolverScheduler$TaskHolder
| 419 | executeBucket$1 in akka.actor.LightArrayRevolverScheduler$$anon$8
| 423 | nextTick in ''
| 375 | run . . . . . . in ''
^ 745 | run in java.lang.Thread
如何解决此问题？谢谢