You receive a "Can't contact LDAP Directory server (81)" error message when you open the Address Book in Outlook

When you open the Address Book in Microsoft Office Outlook 2003, Microsoft Outlook 2002, or Microsoft Office Outlook 2007, you may receive the following error message:

This issue may occur if an address book that uses Internet directory services (LDAP) is configured in Microsoft Outlook, and Outlook cannot contact the LDAP server that is configured for that LDAP address book.

To resolve this issue, use one of the following methods, as appropriate for your situation:

Outlook 2007

• If you are not using Lightweight Directory Access Protocol (LDAP) Internet directory services, remove the LDAP address book. To do this, follow these steps:
  1. Start Outlook.
  2. On the Tools menu, click Account Settings.
  3. On the Address Books tab, click the LDAP address book that you want to remove, and then click Remove.
  4. Click Close.
  5. Exit and restart Outlook.
• If you are using Lightweight Directory Access Protocol (LDAP) Internet directory services, make sure that the settings for the LDAP address book are configured correctly. To do this, follow these steps:
  1. Start Outlook.
  2. On the Tools menu, click Account Settings.
  3. On the Address Books tab, click the LDAP address book that you want to configure, and then click Change.
  4. Verify that the settings for the LDAP server are correct.
  5. Click Next, and then click Close.

Outlook 2002 and 2003

• If you are not using Internet directory services (LDAP), remove the LDAP address book. To do so:
  1. Start Outlook (if it is not already started).
  2. On the Tools menu, click E-mail Accounts.
  3. Under Directory, click View or change existing directories or address books, and then click Next.
  4. Under Directories and Address Books box, click the LDAP address book that you want to remove, and then click Remove.
  5. Click Finish.
  6. Quit, and then restart Outlook.
• If you are using Internet directory services (LDAP), make sure that the settings for the LDAP address book are configured correctly. To do so:
  1. Start Outlook (if it is not already started).
  2. On the Tools menu, click E-mail Accounts.
  3. Under Directory, click View or change existing directories or address books, and then click Next.
  4. Under Directories and Address Books box, click the LDAP address book that you want to configure, and then click Change.
  5. Verify that the settings for the LDAP server are correct.
  6. Click Next, and then click Finish.

Internet directory services (LDAP) are used to find e-mail addresses that are not in a local address book or that are not in a corporate-wide directory such as the Global Address List. Unless the LDAP directory is part of your organization's network, an Internet connection is required to connect to an LDAP server and to view an LDAP address book.