private static TimeSpan? GetTimeRemainingUntilPasswordExpiration()
    {

        Domain d = Domain.GetCurrentDomain();
        string domainName;
        domainName = System.Environment.UserDomainName;

        //These next 2 lines is where I'm getting the error message
        PrincipalContext ctx = new PrincipalContext(ContextType.Domain);
        UserPrincipal user = UserPrincipal.FindByIdentity(ctx, WindowsIdentity.GetCurrent().Name);
        using (System.Web.Hosting.HostingEnvironment.Impersonate())
        {


            TimeSpan? timeSpan = null;

            if (user != null)
            {
                bool passwordNeverExpires = user.PasswordNeverExpires;

                if (!passwordNeverExpires)
                {
                    DirectoryEntry userEntry = (System.DirectoryServices.DirectoryEntry)user.GetUnderlyingObject();
                    IADsUser native = (IADsUser)userEntry.NativeObject;
                    timeSpan = native.PasswordExpirationDate - DateTime.Now;
                    Console.WriteLine(user.GivenName + "'s password will expire on " + native.PasswordExpirationDate);

                }


            }
            return timeSpan;
        }