How to get currentuser in asp.net mvc active directory authenticated app._?

Question

After I login in my ASP.NET MVC app, I need somehow to get the current user login name.

My code is like this:

Startup.cs

 public partial class Startup
 {
        public void Configuration(IAppBuilder app)
        {
           ConfigureAuth(app);
        }
 }

Startup.Auth.cs

public static class ComisionesAuthentication
{
        public const String ApplicationCookie = "xyzAuthenticationType";
}

public partial class Startup
{
        public void ConfigureAuth(IAppBuilder app)
        {
            app.UseCookieAuthentication(new CookieAuthenticationOptions
            {
                AuthenticationType = ComisionesAuthentication.ApplicationCookie,
                LoginPath = new PathString("/Login"),
                Provider = new CookieAuthenticationProvider(),
                CookieName = "xyzCookie",
                CookieHttpOnly = true,
                ExpireTimeSpan = TimeSpan.FromHours(12), // adjust to your needs
            });
        }
}

My AdAuthservice.cs

public class AdAuthenticationService
{
        public class AuthenticationResult
        {
            public AuthenticationResult(string errorMessage = null)
            {
                ErrorMessage = errorMessage;
            }

            public String ErrorMessage { get; private set; }
            public Boolean IsSuccess => String.IsNullOrEmpty(ErrorMessage);
}

private readonly IAuthenticationManager authenticationManager;

public AdAuthenticationService(IAuthenticationManager authenticationManager)
{
    this.authenticationManager = authenticationManager;
}

/// <summary>
/// Check if username and password matches existing account in AD. 
/// </summary>
/// <param name="username"></param>
/// <param name="password"></param>
/// <returns></returns>
public AuthenticationResult SignIn(String username, String password)
{
    //ContextType authenticationType = ContextType.Domain;
    PrincipalContext principalContext = new PrincipalContext(ContextType.Domain);
    bool isAuthenticated = false;

    UserPrincipal userPrincipal = null;
    bool val = false;

    try
    {
        isAuthenticated = principalContext.ValidateCredentials(username, password, ContextOptions.Negotiate);

        if (isAuthenticated)
        {
            userPrincipal = UserPrincipal.FindByIdentity(principalContext, username);
        }
    }
    catch (Exception)
    {
        isAuthenticated = false;
        userPrincipal = null;
    }

    if (!isAuthenticated || userPrincipal == null)
    {
        return new AuthenticationResult("Usuario o contraseña incorrecta");
    }
    else
    {
        var groups = userPrincipal.GetGroups();

        foreach (var item in groups)
        {
            if (item.Name == "AdminC" || item.Name == "ProovedorC")
                val = true;
        }
    }

    if (!val)
    {
        return new AuthenticationResult("No posees permisos para esta aplicación");
    }

    if (userPrincipal.IsAccountLockedOut())
    {
        // here can be a security related discussion weather it is worth 
        // revealing this information
        return new AuthenticationResult("Su cuennta esta bloqueda, contacte un administrador.");
    }

    if (userPrincipal.Enabled.HasValue && userPrincipal.Enabled.Value == false)
    {
        // here can be a security related discussion weather it is worth 
        // revealing this information
        return new AuthenticationResult("Su cuenta esta deshabilitada");
    }

    var identity = CreateIdentity(userPrincipal);

    authenticationManager.SignOut(ComisionesAuthentication.ApplicationCookie);
    authenticationManager.SignIn(new AuthenticationProperties() { IsPersistent = false }, identity);
    //UserPrincipal.Current.Name

    //HttpContext.Current.User.Identity.Name

    //HttpContext.Current.Session.Add("identity", identity);

    return new AuthenticationResult();
}


private ClaimsIdentity CreateIdentity(UserPrincipal userPrincipal)
{
    var identity = new ClaimsIdentity(ComisionesAuthentication.ApplicationCookie, ClaimsIdentity.DefaultNameClaimType, ClaimsIdentity.DefaultRoleClaimType);
    identity.AddClaim(new Claim("http://schemas.microsoft.com/accesscontrolservice/2010/07/claims/identityprovider", "Active Directory"));
    identity.AddClaim(new Claim(ClaimTypes.Name, userPrincipal.SamAccountName));
    identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, userPrincipal.SamAccountName));

    if (!String.IsNullOrEmpty(userPrincipal.EmailAddress))
    {
         identity.AddClaim(new Claim(ClaimTypes.Email, userPrincipal.EmailAddress));
    }

    // add your own claims if you need to add more information stored on the cookie

    return identity;
}

And finally my login action in the controller

[HttpPost]
[AllowAnonymous]
[ValidateAntiForgeryToken]
public virtual ActionResult Index(LoginViewModel model, string returnUrl)
{
        if (!ModelState.IsValid)
        {
            return View(model);
        }

        // usually this will be injected via DI. but creating this manually now for brevity
        IAuthenticationManager authenticationManager = HttpContext.GetOwinContext().Authentication;
        var authService = new AdAuthenticationService(authenticationManager);
        var authenticationResult = authService.SignIn(model.Username, model.Password);

        if (authenticationResult.IsSuccess)
        {
            return RedirectToAction("Index", "Home");
        }

        ModelState.AddModelError("", authenticationResult.ErrorMessage);
        return View(model);
}

The authentication works fine, IsSuccess returns true.

However I can't get the current user logged in, I have tried:

HttpContext.Current.User
UserPrincipal.Current

etc,etc

And it's always empty.

The question is how to get current user after logged in?

Am I missing something in web.config? or a misconfiguration on the app pool?