Validation in dropdown goes wrong in ASP.Net mvc - asp.net-mvc

Question

I have a login page, but whenever I typed wrong credentials it showing the mainheader for login person but with no name.. See the image I attached for further explanations
login
login with wrrong credentials
this is what it look like when the person login successfully, it have name and company
View form
<ul class="nav navbar-nav navbar-right">
#{
AccountContactVM customer = (AccountContactVM)ViewBag.AccountData;
}
#if (customer.User == customer.User && customer.User != null )
{
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown" role="button" aria-expanded="false">
<i class="fa fa-user-circle fa-fw fa-lg" aria-hidden="true"</i>
#customer.User.FirstName #customer.User.LastName
<span class="caret"></span>
</a>
<ul class="dropdown-menu" role="menu">
<li class="disabled">
<div class="row">
<div class="col-md-3">
<i class="fa fa-user-circle" style="font-size:40px;padding:5px 20px;" aria-hidden="true"></i>
</div>
<div class="col-md-9">
<p style="padding-top:5px;">
#customer.User.FirstName #customer.User.LastName
<br />
#customer.Company.AccountName
</p>
</div>
</div>
</li>
<li class="divider"></li>
<li><a asp-controller="Account" asp-action="Index">Customer Portal</a></li>
<li class="divider"></li>
<li><a a asp-controller="Account" asp-action="LogOut">Logout</a></li>
</ul>
</li>
}
else
{
<li><a asp-controller="Account" asp-action="SignUp">Register</a></li>
<li><a asp-controller="Account" asp-action="SignIn"><i class="fa fa-sign-in fa-fw" aria-hidden="true"></i>Login</a></li>
}
<li ng-cloak><span class="glyphicon glyphicon-shopping-cart"></span></i>Cart(<strong>{{CartCount}}</strong>)</li>
</ul>