title: Not able to return messages to Spray HttpService Actor
body: <p>I am learning Spray and Akka. Have built a simple Spray routing App with one of the route stubs as -</p>
  
  <pre><code>path("blog" / LongNumber) {
    blogId =&gt;
      respondWithMediaType(MediaTypes.`application/json`) {
        get {
          request =&gt; BlogFetchActor ! Get(blogId)
        }
      }
   }
  </code></pre>
  
  <p>In the above code I dispatch a message in my spray route definition (in a class implementing HttpService) to another Actor with an ID (blogId) in the request. The BlogFetchActor is supposed to fetch the data from database and respond to the sender. This I have coded as below -</p>
  
  <pre><code>def receive: Receive = LoggingReceive {
    case Get(id: Long) =&gt; {
      log.debug("Retrieving blog with id %d".format(id))
        sender ! ReturnBlog(get(id))
    }
   }
  </code></pre>
  
  <p>The Actor message from the route is getting to my BlogFetchActor. My BlogFetchActor completes the job of getting the data from the database too. But when I try to send the response back to the sender HttpService, the ReturnBlog message, it does not work. The message ends up in DeadLetters and I see the below in my logs -</p>
  
  <blockquote>
    <p>Message [in.bharathwrites.BlogFetchActor$ReturnBlog] from Actor[akka://on-spray-can/user/blog-service/blog#1301907662] to Actor[akka://on-spray-can/deadLetters] was not delivered.</p>
  </blockquote>
  
  <p>Why does the response back to the sender not work? What am I doing wrong? How else can I achieve this? I tried reading the Spray docs and ScalaDoc but could not figure out the problem. Am not proficient enough to read the Spray code and fathom the reasons... Thanks in advance</p>