Using Windows AD in identity server to authenticate user and in that response we are not getting user information like e-mail, first name, last name.

To get the user information, we are using this code:

Thread.GetDomain().SetPrincipalPolicy(PrincipalPolicy.WindowsPrincipal);
WindowsPrincipal principal = (WindowsPrincipal)Thread.CurrentPrincipal;

UserPrincipal up;

using (PrincipalContext pc = new PrincipalContext(ContextType.Domain))
{
     up = UserPrincipal.FindByIdentity(pc, principal.Identity.Name);

     // or return up.GivenName + " " + up.Surname;
}

But it throws an exception “LDAP Server unavailable” and this server can’t be contacted.

How to get the user information without using that unavailable LDAP server?