WebApi 2 Oauth2 Client for Android

I want my android app to communicate with Asp.net WebApi2 secured by Oauth2. All of the samples I've found only show how it's done for websites. I can get the access token from the "/ token" endpoint and I add this token to the http header in the Autorization attribute. However, I always get: "Authorization was denied for this request."

My Auth startup looks like this:

 public partial class Startup
{
    public static OAuthAuthorizationServerOptions OAuthOptions { get; private set; }

    public static string PublicClientId { get; private set; }

    public void ConfigureAuth(IAppBuilder app)
    {
        app.CreatePerOwinContext(ApplicationDbContext.Create);
        app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);



        PublicClientId = "self";
        OAuthOptions = new OAuthAuthorizationServerOptions
        {
            TokenEndpointPath = new PathString("/Token"),
            Provider = new SimmpleApplicationOAuthProvider(PublicClientId),
            AuthorizeEndpointPath = new PathString("/api/Account/ExternalLogin"),
            AccessTokenExpireTimeSpan = TimeSpan.FromDays(14),
            AllowInsecureHttp = true
        };


        app.UseOAuthAuthorizationServer(OAuthOptions);
        app.UseOAuthBearerAuthentication(new OAuthBearerAuthenticationOptions());


    }
}

      

        
        
        
      

    

My SimmpleApplicationOAuthProvider looks like this:

 public class SimmpleApplicationOAuthProvider : OAuthAuthorizationServerProvider
{
    private readonly string _publicClientId;

    public SimmpleApplicationOAuthProvider(string publicClientId)
    {
        if (publicClientId == null)
        {
            throw new ArgumentNullException("publicClientId");
        }

        _publicClientId = publicClientId;
    }

    public override async Task GrantResourceOwnerCredentials(OAuthGrantResourceOwnerCredentialsContext context)
    {
        var userManager = context.OwinContext.GetUserManager<ApplicationUserManager>();

        ApplicationUser user = await userManager.FindAsync(context.UserName, context.Password);

        if (user == null)
        {
            context.SetError("invalid_grant", "The user name or password is incorrect.");
            return;
        }

        var identity = new ClaimsIdentity(context.Options.AuthenticationType);
        identity.AddClaim(new Claim("sub", context.UserName));
        identity.AddClaim(new Claim("role", "user"));

        context.Validated(identity);
    }

    public override async Task ValidateClientAuthentication(OAuthValidateClientAuthenticationContext context)
    {
        context.Validated();
    }

}


 public static class WebApiConfig
{
    public static void Register(HttpConfiguration config)
    {
        // Web API configuration and services
        // Configure Web API to use only bearer token authentication.
        config.SuppressDefaultHostAuthentication();
        config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType));

        // Web API routes
        config.MapHttpAttributeRoutes();

        config.Routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );

        // Enforce HTTPS
        //config.Filters.Add(new LocalAccountsApp.Filters.RequireHttpsAttribute());
    }
}

      

        
        
        
      

    

I am using Wireshark to analyze network traffic. This is my GET request:

GET /LocalAccountsApp/api/values HTTP/1.1
Content-Type: application/json; charset=utf-8
Authorization: Bearer SXFPTU5Sb2JVZWh6M3ZIcEtMRzdiMVVZd3hleTBWbHI2eFZtR2xFSFJQT...
User-Agent: Dalvik/2.1.0 (Linux; U; Android 5.0; LG-D855 Build/LRX21R.A1421650137)
Host: 192.168.1.7
Connection: Keep-Alive
Accept-Encoding: gzip

      

        
        
        
      

    

I put a breakpoint on "GrantResourceOwnerCredentials" and it hits both times (for / token and for / api / values). So where is my call rejected?