XCLN: OWA Clients Receive a "Failed to Connect to the Microsoft Exchange Server" Error Message

If a user uses the Microsoft Exchange Server 5.5 version of Microsoft Outlook Web Access (OWA), the user may intermittently receive the following error message: In some cases, this problem occurs for a time span from one to three minutes. Users cannot log on while this problem occurs, but when the problem stops, OWA continues to function.

However, typically, this problem occurs for a time span that is long enough that the user notices the problem. Typically, the administrator tries to restart Internet Information Services (IIS). If IIS do not restart, the administrator restarts the server.

When this problem occurs, users who are already logged on are not affected. Only new attempts to log on do not work.

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.
Component: MAPI

The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel. Note Because of file dependencies, this fix requires Microsoft Exchange Server version 5.5 Service Pack 4.

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

Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

After you apply this fix on the computer that is running OWA, you must also modify permissions in the registry, and you must add values to the registry for in-process application and out-of-process application:

1. Start Registry Editor (Regedt32.exe).
2. Give the Everyone group or the Authenticated Users group Full Control permissions on the following registry keys:
   • HKEY_LOCAL_MACHINE\Software\Microsoft\Windows Messaging Subsystem\Applications
   • HKEY_LOCAL_MACHINE\Software\Microsoft\Tracing
3. Locate and then click the following key in the registry:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Messaging Subsystem\Applications\INETINFO
4. Add the following values under the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Messaging Subsystem\Applications\INETINFO key:
   • Add the Notification managers value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: Notification managers
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x2
   • Add the Notification Worker Threads value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: Notification Worker Threads
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x2
   • Add the ProfileMemMaxSize value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: ProfileMemMaxSize
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x2000
   • Add the SharedmemMaxSize value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: SharedmemMaxSize
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x10000
   • Add the USEMHEAPMGR value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: USEMHEAPMGR
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x1
   • Add the USEMNOTIFYMGR value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: USEMNOTIFYMGR
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x1
5. Locate and then click the following key in the registry. If the following key does not exist in the registry, create it.
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Messaging Subsystem\Applications\DLLHOST
6. Add the following values under the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Messaging Subsystem\Applications\DLLHOST key:
   • Add the Notification managers value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: Notification managers
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x2
   • Add the Notification Worker Threads value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: Notification Worker Threads
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x2
   • Add the ProfileMemMaxSize value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: ProfileMemMaxSize
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x2000
   • Add the SharedmemMaxSize value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: SharedmemMaxSize
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x10000
   • Add the USEMHEAPMGR value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: USEMHEAPMGR
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x1
   • Add the USEMNOTIFYMGR value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: USEMNOTIFYMGR
     Data type: REG_DWORD
     Radix: Hexadecimal
     Value data: 0x1
   • Add the MHEAPDLLNAME32 value. To do so, on the Edit menu, click Add Value, and then add the following registry value:
     Value name: MHEAPDLLNAME32
     Data type: REG_SZ
     String value data: c:\winnt\system32\exchmem.dll (the location of Exchmem.dll)
7. Quit Registry Editor.