Email .... is already taken

[lifeact]

Hi, thise my code:

View:
`
....
@Html.TextBoxFor(m => m.LoginVK, new { @Class = "form-control" })
@Html.ValidationMessageFor(m => m.LoginVK, "", new { @Class = "text-danger" })

                        @Html.TextBoxFor(m => m.Email, new { @class = "form-control" })
                        @Html.ValidationMessageFor(m => m.Email, "", new { @class = "text-danger" })

....
Controller:
...
[HttpPost]
[AllowAnonymous]
[ValidateAntiForgeryToken]
public async Task ExternalLoginConfirmation(ExternalLoginConfirmationViewModel model, string returnUrl)
{

        try
        {

            if (User.Identity.IsAuthenticated)
            {
                return RedirectToAction("Manage");
            }

            if (ModelState.IsValid)
            {
                // Get the information about the user from the external login provider
                var info = await AuthenticationManager.GetExternalLoginInfoAsync();
                if (info == null)
                {
                    return View("ExternalLoginFailure");
                }
                var user = new ApplicationUser() { UserName = model.LoginVK, Email = model.Email };
                var result = await UserManager.CreateAsync(user);
                if (result.Succeeded)
                {
                    result = await UserManager.AddLoginAsync(user.Id, info.Login);
                    if (result.Succeeded)
                    {
                        
                        await SignInManager.SignInAsync(user, isPersistent: false, rememberBrowser: false);
                        return RedirectToLocal(returnUrl);
                    }
                }
                AddErrors(result);
            }

            ViewBag.ReturnUrl = returnUrl;
            return View(model);

        }

}
...
`
When I click "Войти", I have the error:
Email 'ds......@mail.ua' is already taken
Where my mistake?