LDAP Server is not available - asp.net

Question

I am using LDAP for User Authentication in MVC.My code goes below as follows:
public ActionResult Login(LoginViewModel model, string returnUrl)
{
bool validation;
try
{
LdapConnection ldc = new LdapConnection(new LdapDirectoryIdentifier((string)null, false, false));
NetworkCredential nc = new NetworkCredential(model.UserName, model.Password, "XXXXXXX");
ldc.Credential = nc;
ldc.AuthType = AuthType.Negotiate;
ldc.Bind(nc); // user has authenticated at this point, as the credentials were used to login to the dc.
validation = true;
return RedirectToAction("Index", "Home");
//validation = true;
}
catch (LdapException)
{
validation = false;
}
return View(model);
}
but i am getting an error as "LDAP server not available"
Web.Config:
<authentication mode="Forms">
<forms loginUrl="~/Account/LogOn" timeout="10"/>
</authentication>
<membership defaultProvider="AspNetActiveDirectoryMembershipProvider">
<providers>
<clear />
<add name="AspNetActiveDirectoryMembershipProvider"
type="System.Web.Security.ActiveDirectoryMembershipProvider,System.Web, Version=2.0.0.0,Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"
connectionStringName="ADConnectionString"
attributeMapUsername="sAMAccountName" />
</providers>
</membership>
<add name="ADConnectionString" connectionString="LDAP://XXXXXXX:389/DC=XXXX,DC=XXXX" />

Answer 1

You did not set the path to the LDAP server (currently it is null)
LdapConnection ldc = new LdapConnection(
new LdapDirectoryIdentifier((string)null, false, false)
);
To debug, get rid of try..catch and see where exactly the error comes from. You might need to verify the path with your network administrator or use any tool like LDAP Browser where you could see if path and credentials would work.
Also, make sure that the way you want to authenticate is correct. If this is an intranet application then it might be that you could setup integrated Windows authentication which will not require any custom login process and can be configured on IIS.