I have two problems when submitting from my Ajax login form.

First problem is when i submit the login form without with the correct credentials all works fine, but if I input incorrect details there is any exception when trying to get the current pages id. (The form is a partial view)

The other problem, is again when I input incorrect information, I would like it to return the reason why the user could not log in. For example no account exists with the specified email. But no messages are rendered on the screen when returning the partial. (hits the errors messages fine when debugging)

Can anyone suggest or see what I am doing wrong in with these two issues? Any help in resolving this matter would be very much appreciated.

Umbraco version: 8.6.1

Here is my view/controller code:

View

@inherits UmbracoViewPage<CustomerLogin>
@using QuoteBeater.Models.Membership;

@{
    Model.PageSubmittedFromId = Umbraco.AssignedContentItem.Id;

    Html.EnableClientValidation();
    Html.EnableUnobtrusiveJavaScript();
}

<div id="ajaxLoginForm">
    @using (Ajax.BeginForm("Login", "AccountLogin", new { @id = "loginForm" }, new AjaxOptions { HttpMethod = "POST", InsertionMode = InsertionMode.Replace, UpdateTargetId = "ajaxLoginForm", OnSuccess = "onLoginSuccess" }))
    {

        MembershipViewData result = (MembershipViewData)TempData["LoginModel"];

        if (result != null && !result.Success)
        {
            <div class="alert alert-warning">
                @if (result.Exception != null)
                {
                    <div class="alert alert-danger">
                        <strong>Error:</strong> @result.Exception.Message
                    </div>
                }
                else
                {
                    var message = result.Messages.Aggregate(string.Empty, (current, msg) => current + string.Format("<p>{0}</p>", msg));

                    <div>
                        @Html.Raw(message)
                    </div>
                }
            </div>
        }

        @Html.AntiForgeryToken()
        <div class="form-group">
            @Html.LabelFor(x => x.Username)
            @Html.TextBoxFor(x => x.Username, new { @class = "form-control" })
            @Html.ValidationMessageFor(x => x.Username)
        </div>
        <div class="form-group">
            @Html.LabelFor(x => x.Password)
            @Html.PasswordFor(x => x.Password, new { @class = "form-control" })
            @Html.ValidationMessageFor(x => x.Password)
        </div>
        <div class="form-group ">
            @Html.HiddenFor(x => x.SuccessRedirectUrl)
            @Html.HiddenFor(x => x.PageSubmittedFromId)
            <input type="submit" value="Login" class="btn btn-primary pull-right" />
        </div>
    }
</div>



<script>
    var onLoginSuccess = function (result) {
        if (result.url) {
            window.location.href = result.url;
        }
    }
</script>

Controller (Surface Controller)

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Login(CustomerLogin model)
{
    if (!ModelState.IsValid) return PartialView("~/Views/Partials/Forms/_LoginForm.cshtml", model);

    try
    {
        if (!Members.Login(model.Username, model.Password))
        {
            var member = Members.GetByUsername(model.Username);
            var viewData = new MembershipViewData { Success = false };

            if (member == null)
            {
                viewData.Messages = new[] { "Account does not exist for this email address." };
            }
            else
            {
                var messages = new List<string>
            {
                "Login was unsuccessful with the email address and password entered."
            };

                if (!member.Value<bool>("umbracoMemberApproved")) messages.Add("This account has not been approved.");
                if (member.Value<bool>("umbracoMemberLockedOut")) messages.Add("This account has been locked due to too many unsuccessful login attempts.");

                viewData.Messages = messages;
            }

            TempData["LoginModel"] = viewData;
            return PartialView("~/Views/Partials/Forms/_LoginForm.cshtml", model);
        }
        else
        {

            IPublishedContent currentPage = Umbraco.Content(model.PageSubmittedFromId);

            //If the Login Page else QuoteForm Page
            if (currentPage.IsDocumentType("accountLogin"))
            {
                //https://stackoverflow.com/questions/9391201/ajax-beginform-that-can-redirect-to-a-new-page
                return Json(new { url = "/account" });
            }
            else
            {
                string currentPageUrl = Umbraco.Content(model.PageSubmittedFromId).Url(mode: UrlMode.Absolute);
                return Json(new { url = currentPageUrl });
            }
        }
    }
    catch (Exception ex)
    {
        string exception = ex.Message;
    }

    return PartialView("~/Views/Partials/Forms/_LoginForm.cshtml", model);
}