Login in Asp Net failure

Question

I have want to implement login in asp. net. I can register and AddPassword is true. My password has stored into my database. But when I want to login again it's failed. I got exception here when using CheckPasswordAsync. Here is My code for Register

var result = await UserManager.CreateAsync(user);
var isAddedPassword = await UserManager.AddPasswordAsync(user.Id, model.Password);

Here it is when I want to login

    [HttpPost]
    [AllowAnonymous]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Login(LoginViewModel model, string returnUrl)
    {
        if (!ModelState.IsValid)
        {
            return View(model);
        }
        var foundUser = await UserManager.FindByEmailAsync(model.Email);
        if (foundUser == null)
        {
            ViewBag.Message = "NotRegistered";
            return View();
        }
        var user = await UserManager.FindAsync(foundUser.UserName, model.Password);
        var password = await _userManager.CheckPasswordAsync(foundUser, model.Password);
        var result = await SignInManager.PasswordSignInAsync(foundUser.UserName, model.Password, model.RememberMe, shouldLockout: false);

Any ideas SignInManager.PasswordSignInAsync return failure and CheckPassword got exception?