Applies to: Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2009-03-25

The Availability service for Microsoft Exchange Server 2007 provides calendar information for your users. This information is known as free/busy information. The Autodiscover service provides information for the Availability service by locating and providing the external and internal URLs for the Outlook 2007 client. If your Microsoft Office Outlook 2007 users cannot view calendar information for other Outlook 2007 users in your Exchange 2007 environment, the problem may involve a failure in either the Autodiscover service or the Availability service.

This topic provides information that you can use to determine whether the Autodiscover service or the Availability service cannot provide the necessary information to your users.

Troubleshooting Autodiscover Connectivity in Outlook 2007

You can use Outlook 2007 to troubleshoot problems with the Autodiscover service. To determine whether the Autodiscover service is unable to provide information to clients by using Outlook 2007, log on to the mailbox of the user for whom you want to troubleshoot Autodiscover connectivity, and then follow these steps:

  1. In Outlook 2007, on the Tools menu, click Options, click the Other tab, and then click Advanced Options.

  2. On the Advanced Options page, select Enable logging (troubleshooting), and then click OK.

  3. Restart Outlook 2007, and then try to view free/busy information for another user.

  4. In Microsoft Windows, click Start, click Run, and then type %temp%.

  5. In Windows Explorer, open the olkdisc.log file and locate the files in the olkas directory.

  6. The information that is contained in this directory can frequently provide information about which service is not functioning correctly.

You can also use Outlook 2007 to test the AutoConfiguration information that is provided by the Autodiscover service. To use the Outlook 2007 client to test AutoConfiguration by using Outlook 2007, log on to the mailbox of the user for whom you want to test the AutoConfiguration, and then do the following:

  1. While Outlook 2007 is running, hold down the CTRL key, right-click the Outlook icon in the notification area, and then select Test E-mail AutoConfiguration.

  2. Verify that the correct e-mail address is in the box next to E-mail Address.

  3. Clear the check boxes next to Use Guessmart and Secure Guessmart Authentication.

  4. On the Test E-mail AutoConfiguration page, verify that the check box next to Use AutoDiscover is selected, and then click the Test button.

The following table provides a brief description of error codes that may occur when you test the AutoConfiguration for the Autodiscover service in Outlook 2007.

AutoConfiguration Error Codes in Outlook 2007

Error Code Description


This error is usually caused by a missing host record for the Autodiscover service in the Domain Naming service.


This error is usually caused by an incorrect certificate configuration on the Exchange 2007 computer that has the Client Access server role installed.


This error is usually caused by issues that are related to Domain Naming service.


This error is usually caused by incorrect security settings in Outlook 2007.

Troubleshooting the Availability Service in Exchange 2007

Exchange 2007 provides two ways for you to determine whether the Availability service is not functioning correctly.

Using the Event Log to Troubleshoot the Availability Service

Review the application event log on the Exchange 2007 Client Access server and check for events that are generated by the Availability service. For more information about how to use the Application event log, see Checking the Event Viewer. The following list describes common events that are associated with the Availability service:

  • 4001 The Availability service could not discover an Availability service in the remote forest   If you see this event, verify that the Autodiscover service in the remote forest is functioning correctly.

  • 4003 PublicFolderRequestFailed   This event usually indicates a failure to look up free/busy information for legacy mailboxes. Typically, this information comes from public folders. This error may occur if public folder replication has not been configured correctly. Or, this error may occur as a result of specific settings on the /public virtual directory. The description of this event will usually include the URL to the target public folder and one of the following HTTP errors:

    • 401   Typically, this HTTP error occurs if Integrated Windows authentication is disabled on the /public virtual directory. This often occurs when the Availability service that is running on Exchange 2007 tries to make a connection with the /public virtual directory in IIS on an Exchange 2003 Mailbox server that is configured to use forms-based authentication (FBA). When FBA is enabled, all other authentication methods, including Integrated Windows Authentication, are automatically disabled.

    • 403   This HTTP error may occur if the Client Access server is offline or if it does not contain a replica. Or, this error may occur if the Availability service connects to a Mailbox server that has Secure Sockets Layer (SSL) enabled on the /public virtual directory. Typically, this occurs when Exchange 2003 Mailbox servers are configured to use forms-based authentication and Exchange 2007 is deployed with both the Mailbox and Client Access server roles installed on the same computer. Connections between the Outlook client and the Availability service use HTTPS over port 443. However, connections between the Availability service and the /public virtual directory use HTTP over port 80.

    • 404   This HTTP error can occur if the /public virtual directory could not be found.

  • 4005 Could not find information in Active Directory to allow cross-forest requests   If you see this event, you must configure the Availability service across forests. For more information about this issue, view the topic How to Configure the Availability Service for Cross-Forest Topologies.

  • 4011 Cross-forestRequestFailed   This usually indicates a failure to locate an AvailabilityAddressSpace object that is required to proxy the Availability service request to a different forest. For more information about this issue. View the topic Add-AvailabilityAddressSpace (RTM).

Using the Test-OutlookWebServices Cmdlet to Troubleshoot the Availability Service

You can use the Test-OutlookWebServices cmdlet in the Exchange Management Shell to determine whether the Availability service is functioning correctly. To perform the following procedure, the account you use must be delegated the Exchange Organization Administrator role.

For more information about permissions, delegating roles, and the rights that are required to administer Exchange Server 2007, see Permission Considerations.

To use the Exchange Management Shell to test the Availability service
  • Run the following command:

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    Test-OutlookWebServices -TargetAddress:

For more information about syntax and parameters, see Test-OutlookWebServices.

The resulting output in the Exchange Management Shell will provide error details about the Availability service. For more information, see How to Diagnose Availability Service Issues.

Modifying the Time Limit of a Cross-Forest Autodiscover Service Request

The cross-forest Availability service has a time limit when the service performs an Autodiscover service request for cross-forest users in the Active Directory directory service. By default, this time-out value is 10 seconds. If the Autodiscover request does not finish in 10 seconds, the Availability service request for the cross-forest user may time out.

An Autodiscover request may not finish in the time-out period if one or more of the following conditions are true:
  • The URL for the user is not cached.

  • The Autodiscover service is running slowly.

  • The Autodiscover service experiences network latencies.

You can use the RecipientResolutionTimeoutInSeconds property to control the time-out value. This property is set in the ASP.NET Web.config file. The default value of this property is 10 seconds. The following procedure describes how to modify the time-out value for the cross-forest Availability service.

To change the RecipientResolutionTimeoutInSeconds value by using Notepad
  1. Locate the Outlook Web Access Web.config file on the Client Access server. The default location is in the following directory: <drive>\Program Files\Microsoft\ExchangeServer\ClientAccess\Owa.

  2. Make a backup copy of this file.

  3. Open the original file by using Notepad. Do not use IIS to edit the Web.config file.

  4. Add the following section directly under the <Configuration> node after the <appSettings> section:

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    <add key="RecipientResolutionTimeoutInSeconds" value="24"/>
    If you add this section under any other node of the Web.config file, the section will not work.
  5. Save the Web.config file.

We recommend that you do not set this property to a value of more than 25 seconds.

For More Information

For more information about the Autodiscover service, see the following topics:

For more information about the Availability service, see the following topic: