Session Variables Lost after ReDirect - asp.net-mvc-4

Question

I have an MVC site that is using membership providers for authenticating against multiple domains.
I am using SESSION to store the displayName of my user that I then display in my _Layout.cshtml
This all works perfectly on my localhost, but when I deploy my app to VM/Server the SESSION is null and i get Object not set to an instance of an object and the error points to the line in my layout page where i display the full username. This happens after session timeout and user requests a new page and are required to login again.
Here is my Login method:
if (!ModelState.IsValid)
{
return View(model);
}
Session["UserName"] = "Unknown User";
Logger.Instance.Info("Setting username to unknown user");
var msg = string.Empty;
var user = _userSvc.GetLoginUserData(model.Username, out msg);
if (!string.IsNullOrEmpty(msg))
{
Logger.Instance.Info("getting user info but error returned: "+msg);
ModelState.AddModelError("", msg);
return View(model);
}
Logger.Instance.Info("User was found "+user.EMAIL);
foreach (MembershipProvider provider in Membership.Providers)
{
var username = user.LEGACY_USERNAME;
if (provider.Name == "ADENTMembershipProvider") username = user.ENT_USERNAME;
try
{
Logger.Instance.Info("Authenticating user "+username+" to "+provider.Name);
if (provider.ValidateUser(username, model.Password))
{
Session["UserName"] = user.FIRST_NAME + ' ' + user.LAST_NAME;
Logger.Instance.Info("User authenticated " + Session["UserName"]);
var authTicket = new FormsAuthenticationTicket(
1, // version
user.ID.ToString(), // user name
DateTime.Now, // created
DateTime.Now.AddMinutes(2), // expires
false, // persistent?
user.ROLE // can be used to store roles
);
string encryptedTicket = FormsAuthentication.Encrypt(authTicket);
var authCookie = new HttpCookie(FormsAuthentication.FormsCookieName, encryptedTicket);
Response.Cookies.Add(authCookie);
if (returnUrl != null && returnUrl != "/")
{
Logger.Instance.Info("Redirecting user to " + returnUrl);
Response.Redirect(returnUrl);
}
else
{
return RedirectToAction("Index", "Home");
}
}
}
catch (Exception ex)
{
Logger.Instance.Error("Error authenticating user " + username + " to " + provider.Name, ex);
}
}
SynLogger.Instance.Info("User could not be authenticated " );
// User was not authenticated in any of the AD
ModelState.AddModelError("", "Invalid login attempt. The username or password provided is incorrect.");
return View(model);
Here is the line in my layout that is causing the issue when session times out and user re-logs in:
Hello #Html.Raw(Session["UserName"].ToString())
Not sure why it works on my development machine but not when I deploy to server.
Is there another way I can store the username other than SESSION so I can access it my layout page?