akka.cluster with double asp.net webapi on IIS

In out cluster we have five nodes composite of:

• 2 seed nodes (backend)
• 1 worker
• 2 webapi on IIS

The cluster is joined, up and running; but the second IIS when perform the first message to the cluster via router make all cluster unreachable and dissociated. In addition the second IIS can't deliver any message.

Here is my IIS config:

<hocon>
  <![CDATA[
        akka.loglevel = INFO
        akka.log-config-on-start = off
        akka.stdout-loglevel = INFO
        akka.actor {
            provider = "Akka.Cluster.ClusterActorRefProvider, Akka.Cluster"
            deployment {
              /Process {
                router = round-robin-group
                routees.paths = ["/user/Process"] # path of routee on each node
                # nr-of-instances = 3 # max number of total routees
                cluster {
                    enabled = on
                    allow-local-routees = off
                    use-role = Process
                }
              }
            }
            debug {
              receive = on
              autoreceive = on
              lifecycle = on
              event-stream = on
              unhandled = on
            }
        }
        akka.remote {
            helios.tcp {
                # transport-class = "Akka.Remote.Transport.Helios.HeliosTcpTransport, Akka.Remote"
                # applied-adapters = []
                # transport-protocol = tcp
                port = 0
                hostname = 172.16.1.8
            }
            log-remote-lifecyclo-events = DEBUG
        }
        akka.cluster {
          seed-nodes = [
            "akka.tcp://ClusterActorSystem@172.16.1.8:2551",
            "akka.tcp://ClusterActorSystem@172.16.1.8:2552"
          ]
          roles = [Send]
          auto-down-unreachable-after = 10s
          # how often should the node send out gossip information?
          gossip-interval = 1s
          # discard incoming gossip messages if not handled within this duration
          gossip-time-to-live = 2s
        }
        # http://getakka.net/docs/persistence/at-least-once-delivery
        akka.persistence.at-least-once-delivery.redeliver-interval = 300s
        # akka.persistence.at-least-once-delivery.redelivery-burst-limit =
        # akka.persistence.at-least-once-delivery.warn-after-number-of-unconfirmed-attempts =
        akka.persistence.at-least-once-delivery.max-unconfirmed-messages = 1000000
        akka.persistence.journal.plugin = "akka.persistence.journal.sql-server"
        akka.persistence.journal.publish-plugin-commands = on
        akka.persistence.journal.sql-server {
            class = "Akka.Persistence.SqlServer.Journal.SqlServerJournal, Akka.Persistence.SqlServer"
            plugin-dispatcher = "akka.actor.default-dispatcher"
            table-name = EventJournal
            schema-name = dbo
            auto-initialize = on
            connection-string-name = "HubAkkaPersistence"
            refresh-interval = 1s
            connection-timeout = 30s
            timestamp-provider = "Akka.Persistence.Sql.Common.Journal.DefaultTimestampProvider, Akka.Persistence.Sql.Common"
            metadata-table-name = Metadata
        }
        akka.persistence.snapshot-store.plugin = ""akka.persistence.snapshot-store.sql-server""
        akka.persistence.snapshot-store.sql-server {
          class = "Akka.Persistence.SqlServer.Snapshot.SqlServerSnapshotStore, Akka.Persistence.SqlServer"
          plugin-dispatcher = ""akka.actor.default-dispatcher""
          connection-string-name = "HubAkkaPersistence"
          schema-name = dbo
          table-name = SnapshotStore
          auto-initialize = on
        }
  ]]>
</hocon>

inside the global.asax we create a new router to the cluster:

    ClusterActorSystem = ActorSystem.Create("ClusterActorSystem");

    var backendRouter =
        ClusterActorSystem.ActorOf(
            Props.Empty.WithRouter(FromConfig.Instance), "Process");

    Send = SistemiHubClusterActorSystem.ActorOf(
        Props.Create(() => new Common.Actors.Send(backendRouter)),
        "Send");

and here is our backend config:

<hocon><![CDATA[
    akka.loglevel = INFO
    akka.log-config-on-start = on
    akka.stdout-loglevel = INFO
    akka.actor {
        provider = "Akka.Cluster.ClusterActorRefProvider, Akka.Cluster"
        debug {
          receive = on
          autoreceive = on
          lifecycle = on
          event-stream = on
          unhandled = on
        }
    }
    akka.remote {
      helios.tcp {
            # transport-class = "Akka.Remote.Transport.Helios.HeliosTcpTransport, Akka.Remote"
            # applied-adapters = []
            # transport-protocol = tcp
            # 
            # seed-node ports 2551 and 2552
            # non-seed-node port 0
            port = 2551
            hostname = 172.16.1.8
        }
        log-remote-lifecyclo-events = INFO
    }
    akka.cluster {
      seed-nodes = [
        "akka.tcp://ClusterActorSystem@172.16.1.8:2551",
        "akka.tcp://ClusterActorSystem@172.16.1.8:2552"
      ]
      roles = [Process]
      auto-down-unreachable-after = 10s
    }
  ]]></hocon>

The issue in present using Akka 1.1 and Akka 1.2

UPDATE

I have found that the issue is related to our LoadBalancer (NetScaler) if I call each IIS directly is working fine. If called by the balancer I face the reported issue; the balancer is trasparent (it only add some headers to the request). What can I check to solve this issue?

Finally I found the problem, we are using akka.persistence that requires a specific value declination for the PersistenceId for each IIS.