android signalR hubconnection application negotiation failed with server

hi i'm new in android developing and i want to write an application which use signalR java-client. in first step i did the answer of this and here is my client code:

Platform.loadPlatformComponent(new AndroidPlatformComponent());
String host = "localhost";
HubConnection connection = new HubConnection( host);
HubProxy hub = connection.createHubProxy("HubConnectionAPI");

SignalRFuture<Void> awaitConnection = connection.start(new LongPollingTransport(connection.getLogger()));
try {
    awaitConnection.get();
} catch (InterruptedException e) {
    e.printStackTrace();
} catch (ExecutionException e) {
    e.printStackTrace();
}

hub.subscribe(this);
try {
    hub.invoke("DisplayMessageAll", "message from android client").get();
    System.out.println("sent!!!");
} catch (InterruptedException e) {
    e.printStackTrace();
} catch (ExecutionException e) {
    e.printStackTrace();
}

and u can download the server code from here

i have following error with awaitConnection.get();

error:

W/System.err: java.util.concurrent.ExecutionException: microsoft.aspnet.signalr.client.transport.NegotiationException: There was a problem in the negotiation with the server

i also have this error:

Caused by: microsoft.aspnet.signalr.client.http.InvalidHttpStatusCodeException:Invalid status code: 404

can anyone please help me? i searched a lot but i didn't found anything helpful for me

EDIT:

clients can access the hub via this but how can i implement on android so my application can connect?

this is the log file on server:

2015-11-11 09:05:08 10.2.0.18 GET /signalr/negotiate clientProtocol=1.3&connectionData=%5B%7B%22name%22%3A%22hubconnectionapi%22%7D%5D 80 - 10.2.0.253 SignalR+(lang=Java;+os=android;+version=2.0) - 404 0 2 3