ModelState.AddModelError not displaying error in view - ASP.NET
<p>I have been banging my head against the wall trying to solve this issue.</p>

<p>I have this view controller</p>

<pre><code>public class LoginController : Controller
    {
        public ActionResult Index(LoginClass model)
        {
            return View(model);
        }

        [HttpPost]
        public ActionResult Login(LoginClass model, string ReturnUrl)
        {

            if (!this.ModelState.IsValid)
            {
                return this.View(model);
            }

            if (ModelState.IsValid)
            {
                if (Membership.ValidateUser(model.UserName, model.Password))
                {
                    FormsAuthentication.SetAuthCookie(model.UserName, model.RememberMe);
                    if (Url.IsLocalUrl(ReturnUrl) &amp;&amp; ReturnUrl.Length &gt; 1 &amp;&amp; ReturnUrl.StartsWith("/")
                        &amp;&amp; !ReturnUrl.StartsWith("//") &amp;&amp; !ReturnUrl.StartsWith("/\\"))
                    {
                       return Redirect(ReturnUrl);
                    }
                    else
                    {
                        return RedirectToAction("Index", "Home");
                    }
                }
                else
                {
                    ModelState.AddModelError(string.Empty, "The user name or password provided is incorrect");
                }


            }

            return RedirectToAction("Index", "Login", model);

        }

        public ActionResult Logout()
        {
            FormsAuthentication.SignOut();

            return RedirectToAction("Index", "Home");
        }

    }
</code></pre>

<p>and here is my view:</p>

<pre><code>&lt;section id="login"&gt;
    &lt;div class="container"&gt;
        &lt;form action="~/Login/Login" id="Login" method="post"&gt;
            &lt;div class="row"&gt;
                &lt;div class="col-md-12"&gt;
                    &lt;p&gt;
                        &lt;label for="username"&gt;Username&lt;/label&gt;
                        &lt;input type="text" id="username" name="username" class="form-control" /&gt;
                    &lt;/p&gt;
                &lt;/div&gt;
            &lt;/div&gt;
            &lt;div class="row"&gt;
                &lt;div class="col-md-12"&gt;
                    &lt;p&gt;
                        &lt;label for="password"&gt;Password&lt;/label&gt;
                        &lt;input type="password" id="password" name="password" class="form-control" /&gt;
                    &lt;/p&gt;
                &lt;/div&gt;
            &lt;/div&gt;
            &lt;div class="row"&gt;
                &lt;div class="col-md-12"&gt;
                    &lt;p&gt;
                        &lt;input type="submit" id="submit" name="submit" value="Login" class="btn btn-default" /&gt;
                    &lt;/p&gt;
                &lt;/div&gt;
            &lt;/div&gt;
            &lt;div class="row"&gt;
                &lt;div class="col-md-12"&gt;
                    &lt;p&gt;
                        &lt;label for="password"&gt;Remember Me?&lt;/label&gt;
                        &lt;input type="checkbox" id="chkPersist" name="chkPersist" /&gt;
                    &lt;/p&gt;
                &lt;/div&gt;
            &lt;/div&gt;
            &lt;div class="row"&gt;
                &lt;div class="col-md-12"&gt;
                    &lt;p&gt;
                        @Html.ValidationSummary()
                    &lt;/p&gt;
                &lt;/div&gt;
            &lt;/div&gt;
        &lt;/form&gt;
    &lt;/div&gt;
&lt;/section&gt;
</code></pre>

<p>My issue is that my error message is not appearing when I enter the wrong username and password. Why is not displaying?</p>