HTTP 401 or 404 error messages when you access OWA implicitly or explicitly

When you try to log on to Outlook Web Access (OWA) implicitly (that is, you do not append the URL with your alias), you may receive one of the following error messages:

Error Message 1

Error Message 2

Error Message 3

When you examine the Microsoft Internet Information Services (IIS) log files, you will see a 401.5 error code. The IIS log files are typically found in the Windows\System32\LogFiles\W3SVC1 directory.

When you try to log on to OWA explicitly (that is, you append the URL with your alias), you may receive the following error message: When this issue occurs, you can still access your mailbox by using the Microsoft Outlook MAPI client.

This issue occurs if the user account that you used to log on to OWA does not have an appropriate Simple Mail Transfer Protocol (SMTP) address.

This issue generally occurs when you move users from a Microsoft Exchange Server 5.5 computer to a Microsoft Exchange 2000 Server or Microsoft Exchange Server 2003 computer, or when you upgrade an Exchange 5.5 computer to Exchange 2000 or Exchange 2003 and the default naming policy in your Exchange 2000 or Exchange 2003 organization is different from the naming policy in the Exchange 5.5 site.

This is a core Web Distributed Authoring Version (DAV) architectural issue. To find the mailbox that is associated with a URL, DAV uses the values in the proxyAddresses attribute of the user object, and then compares these values against the domain and the Exchange virtual directory to find a match with a unique object in the directory.

See the "More Information" section for information about how to determine the appropriate SMTP address and the default e-mail proxy address that is generated by Exchange 2000.

Note The Web DAV address check is not present in Microsoft Exchange 2003 Service Pack 1.

Exchange 2003

To resolve this issue, obtain the latest service pack for Exchange Server 2003. For more information, click the following article number to view the article in the Microsoft Knowledge Base: Note Installing Microsoft Exchange Server 2003 Service Pack 1 (SP1) resolves this issue only if users log on to OWA implicitly. If users log on to OWA explicitly, they may still receive the following error message:

Exchange 2000

To resolve this issue, use one of the following methods:

• Modify the SMTP address or add a new SMTP address for the users who are encountering the issue in the "Symptoms" section. You may want to use this method if the issue is confined to some users or to users who have incorrect SMTP addresses.
• Modify the SMTP domain serviced by the Exchange virtual directory. You may want to use this method if most or all of the users in your organization are encountering the issue in the "Symptoms" section.
• Create additional virtual directories for additional SMTP domains. You may want to use this method if your organization has multiple SMTP domains or if you are using Exchange 2000 for hosting.
  
  Note You can also create additional HTTP Virtual Servers for additional SMTP domains. This process is more involved than this article addresses. For more information about how to set up additional HTTP virtual servers, visit the online Help for Exchange 2000 at the following Microsoft Web site:
  http://technet.microsoft.com/en-us/library/aa997016.aspx (http://technet.microsoft.com/en-us/library/aa997016.aspx)

Method 1: Modify or add an SMTP address to a user

1. Determine the SMTP domain by examining the Mailboxes for SMTP domain value in the Exchange virtual directory that serves the SMTP domain. To do this, follow these steps:
   1. Start Exchange System Manager.
   2. Expand Administrative Groups, expand Servers, expand ServerName, expand Protocols, expand HTTP, expand Exchange Virtual Server, and then expand Exchange.
   3. Right-click the Exchange virtual directory, and then click Properties.
   4. Note the SMTP domain that is listed under the Mailboxes for SMTP domain box.
2. Start the Active Directory Users and Computers snap-in.
3. Locate the user account in the console tree, right-click the user account, and then click Properties. By default, a user is created in the user's organizational unit (OU), but the user can exist in more than one OU.
4. Click the E-mail Addresses tab.
5. To add an SMTP address for this user, click New, double-click SMTP Address, and then type an address that matches the Mailboxes For SMTP domain value in the properties of the Exchange virtual directory that you obtained in step 1.
6. To modify an existing SMTP address, click the address that you want to modify, click Edit, and then type an address that matches the Mailboxes for STMP domain value in the properties of the Exchange virtual directory.
7. Click OK two times.

It may take some time for Active Directory to replicate the new address before this user can log on to OWA.

Note The default (bold) SMTP address of a user does not have to match the Mailboxes For value. The user should be able to log on if any one of the SMTP addresses match the value.

Method 2: Modify the SMTP domain that is serviced by the Exchange virtual directory

In the Properties dialog box for the Exchange virtual directory, the Modify button is not available (appears dimmed). This behavior occurs because the SMTP domain that is used by the Exchange virtual directory is always the default SMTP domain that is assigned by the Default Recipient Policy.

To modify the default SMTP domain, follow these steps.

Note These steps include restarting the Microsoft Exchange information store and its dependent services. While the information store is stopped, no clients can access e-mail.

1. Start Exchange System Manager.
2. Expand the Recipients container.
3. Select the Recipient Policies object.
4. In the right pane, locate the Default Policy and obtain the properties.
5. Click the E-mail Addresses tab.
6. Double-click the SMTP address. If there is more than one SMTP address listed, double-click the SMTP address that appears in bold.
7. Leave the at sign (@) at the beginning, and then type the SMTP domain that you want in the Address field.
8. Click OK two times.
9. Start the Services snap-in.
10. Click the Microsoft Exchange Information Store service.
11. Click Restart Service on the Microsoft Management Console (MMC) toolbar. When you are prompted to restart the dependent services, click Yes. The Mailboxes For value will be updated to use your new SMTP domain.

Method 3: Create additional virtual directories for additional SMTP domains

Note If the computer uses front-end servers and back-end servers, you must create the virtual directories on both the front-end servers and the back-end servers.

1. Start Exchange System Manager.
2. Expand Servers, expand ServerName, expand Protocols, expand HTTP, and then expand Exchange Virtual Server.
3. Right-click the Exchange virtual server, click New, and then click Virtual Directory.
4. Type the name of the new virtual directory.
   
   This name will appear in the URL that is used by clients to access the new virtual directory. For example, if you create a new virtual directory named companybmail, clients will use a URL that is similar to http://www.domain.com/companybmail/.
5. To select an SMTP domain, click the Modify button, and then select an SMTP domain from the list.
   
   Note This list is generated from all SMTP Address values in all recipient policies that are defined in your Exchange organization. You cannot supply an SMTP domain that does not appear in this list.

For more information about recipient policy management, see the "Managing Recipient Settings" topic in the Exchange 2000 online help topic at the following Microsoft Web site: To customize authentication methods, click the Authentication button on the Access tab of Exchange System Manager.

To determine the appropriate SMTP address, follow these steps:

1. Start Exchange System Manager.
2. Expand Servers, expand ServerName, expand Protocols, expand HTTP, expand Exchange Virtual Server, and then expand Exchange.
3. Right-click the Exchange virtual directory, and then click Properties to view the properties of the Exchange virtual directory. This is the default OWA virtual directory created during Exchange Server Setup.
4. On the General tab, note the value from the field labeled Exchange Path. An example of this value is example.com (default). In this example, only users who have an SMTP address ending with @example.com can use the Exchange virtual directory to access their mailboxes.

To determine the default e-mail proxy address that is generated by Exchange 2000:

1. Start the Exchange System Manager snap-in.
2. Expand Recipients, and then click Recipient Policies.
3. In the right pane, double-click Default Policy, and then click the E-Mail Addresses (Policy) tab.
4. Under Generation rules, double-click the SMTP address that appears bold.
5. In the Address box, note the configuration parameters (if any) that appear before the at sign (@). For example, these parameters may include %s or %g.

These parameters are used to generate the recipient e-mail address that is based on user account information. For example, the %s.%g@example.com parameter causes Exchange 2000 to generate the following e-mail address:

surname.givenname@example.com