ASP.Net Owin身份，注册成功但无法登录

Question

My Startup.Auth.cs如下

[assembly: OwinStartup(typeof(IoTWeb.App_Start.Startup))]

namespace IoTWeb.App_Start
{
    public class Startup
    {
        private const int DEFAULTTIMEOUT = 5;
        private const int DEFAULTEXPIRETIMESPAN = 5;
        public void Configuration(IAppBuilder app)
        {
            // Enable the application to use a cookie to store information for the signed in user
            app.UseCookieAuthentication(new CookieAuthenticationOptions
            {
                AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
                LoginPath = new PathString("/Account/Login")
            });

            app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);

            // Enable the application to use a cookie to store information for the signed in user
            // and to use a cookie to temporarily store information about a user logging in with a third party login provider
            // Configure the sign in cookie
            app.UseCookieAuthentication(new CookieAuthenticationOptions
            {
                AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
                LoginPath = new PathString("/Account/Login"),
                Provider = new CookieAuthenticationProvider
                {
                    OnValidateIdentity =
                         SecurityStampValidator.OnValidateIdentity<ApplicationUserManager, User>(TimeSpan.FromMinutes(DEFAULTTIMEOUT),
                             (manager, user) => Task.FromResult(manager.CreateIdentity(user, DefaultAuthenticationTypes.ApplicationCookie)))
                },
                SlidingExpiration = true,
                ExpireTimeSpan = TimeSpan.FromMinutes(DEFAULTEXPIRETIMESPAN)
            });

            // Use a cookie to temporarily store information about a user logging in with a third party login provider
            app.UseExternalSignInCookie(DefaultAuthenticationTypes.ExternalCookie);
        }
    }

和我的UserStoreService.cs

public class UserStoreService : IUserStore<User>, IUserPasswordStore<User>, IUserEmailStore<User>
{
    private readonly TenantEntities context = new TenantEntities();

    public Task<User> Find(string userName, string password)
    {
        Task<User> task = context.User.Where(
            apu => apu.UserName == userName && apu.Password == password)
            .FirstOrDefaultAsync();
        return task;
    }

我的帐户控制器

public  ActionResult Login(LoginViewModel model, string returnUrl)
{
    if (ModelState.IsValid)
    {
        var manager = HttpContext.GetOwinContext().GetUserManager<ApplicationUserManager>();
        User user = manager.Find(model.UserName, model.Password);
        if (user != null)
        {
            IAuthenticationManager authenticationManager = HttpContext.GetOwinContext().Authentication;
            authenticationManager.SignOut(DefaultAuthenticationTypes.ExternalCookie);
            ClaimsIdentity identity = manager.CreateIdentity(user, DefaultAuthenticationTypes.ApplicationCookie);
            authenticationManager.SignIn(new AuthenticationProperties { IsPersistent = false }, identity);
            return RedirectToLocal(returnUrl);
        }
    }

    // If we got this far, something failed, redisplay form
    ModelState.AddModelError("", "Login failed due to incorrect credentials.");
    return View(model);
}

[AllowAnonymous]
public ActionResult Register()
{
    // Remove the Cookie in Here as he goes a bit further
    if (ControllerContext.HttpContext.Request.Cookies.AllKeys.Contains("FinancesModelDataCookie"))
    {
        HttpCookie cookie = ControllerContext.HttpContext.Request.Cookies["FinancesModelDataCookie"];
        if (cookie != null)
        {
            cookie.Expires = DateTime.Now.AddDays(-1);
            ControllerContext.HttpContext.Response.Cookies.Add(cookie);
        }
    }
    return View();
}

注册成功，但登录卡在

User user = manager.Find(model.UserName, model.Password); 

并提供以下异常

这里编辑的是Identity.Config

public class ApplicationUserManager : UserManager<User>
{
    public ApplicationUserManager()
        : base(new UserStoreService())
    {
    }

    public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options,
        IOwinContext context)
    {
        var manager = new ApplicationUserManager();
        manager.PasswordHasher = new PasswordHasher(); // new NoPasswordHasher();


        // Configure validation logic for usernames
        manager.UserValidator = new UserValidator<User>(manager)
        {
            AllowOnlyAlphanumericUserNames = false,
            RequireUniqueEmail = true
        };

        //Configure validation logic for passwords
        manager.PasswordValidator = new PasswordValidator
        {
            RequiredLength = 6,
            RequireNonLetterOrDigit = true,
            RequireDigit = true,
        };
        manager.PasswordValidator = new CustomPasswordValidator(6);       //commented for and used above defined validator

        //manager.RegisterTwoFactorProvider("EmailCode", new EmailTokenProvider<User>
        //{
        //    Subject = "SecurityCode",
        //    BodyFormat = "Your security code is: {0}"
        //});
        manager.EmailService = new EmailService();

        IDataProtectionProvider dataProtectionProvider = options.DataProtectionProvider;
        if (dataProtectionProvider != null)
        {
            manager.UserTokenProvider = new DataProtectorTokenProvider<User>(dataProtectionProvider.Create("ASP.NET Identity"));
        }
        return manager;
    }
}