Error messages when you try to connect Outlook 2007 to Exchange Server: "The action cannot be completed" or "Your Microsoft Exchange Server is unavailable" or "Cannot start Microsoft Office Outlook"

When you try to connect Microsoft Office Outlook 2007 to Microsoft Exchange Server, you may experience any one of the following symptoms:

• If your Outlook profile has been automatically configured, you may receive the following error message:
  The action cannot be completed. The connection to the Microsoft Exchange Server is unavailable. Your network adapter does not have a default gateway.
• If your Outlook profile has been manually configured, you may receive the following error message:
  Your Microsoft Exchange Server is unavailable
  For example, this error may occur when you have an existing profile that was previously connected to the Exchange Server, and then you lose the setting for your default gateway. In this scenario, if you click Check Name to verify your settings in the E-mail Accounts dialog box, you may receive the following error message:
  Outlook cannot log on. Verify that you are connected to the network and are using the proper server and mailbox name. The connection to the Microsoft Exchange Server is unavailable. Your network adapter does not have a default gateway.

When you try to connect Outlook 2007 to Microsoft Exchange Server 2003 by using RPC over HTTPS, you may receive the following error message:

This problem may occur if the Outlook 2007 client computer does not have a default gateway configured.

If you cannot configure a default gateway for your network settings, you can work around this problem by adding a DWORD value that is named DefConnectOpts to the following registry subkey: To add this DWORD value, follow these steps.

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

1. Click Start, click Run, type regedit in the Open box, and then click OK.
2. Locate and then click the following subkey:
   HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\RPC
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type DefConnectOpts, and then press ENTER.
5. Right-click DefConnectOpts, and then click Modify.
6. In the Value data box, type 0, and then click OK.
7. Exit Registry Editor.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.