Unknown Error (0x80005000)

I have been trying to authenticate username and password using LDAP, but I get a Message Box showing Unknown Error:(0x80005000).Once I close the Unknown Error Message Box it displays the Login screen but does not perform authentication.

Please suggest some solution

The code which I have used is as follows:

/// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class Login : Window
    {
        public Login()
        {
            InitializeComponent();
            AddData adminScreen = new AddData();

           

            string username = textBoxUsername.Text;
            string password = Convert.ToString(passwordBox.Password);

            DirectoryEntry entry = new DirectoryEntry("LDAP://corporate.adcorp.com/xyz.com/dc=xyz,dc=com", username, password);
            try
            {
                Object obj = entry.NativeObject;
                DirectorySearcher search = new DirectorySearcher(entry);
                search.Filter = ("(sAMAccountName=" + username + ")");
                search.PropertiesToLoad.Add("cn");
                SearchResult result = search.FindOne();
                if (result != null)
                {
                    adminScreen.Show();
                    this.Close();
                }

            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.Message.ToString());
            }
        }            
    }

Tags: C# (C# 4.0), LDAP, Authentication