An Outlook 2007 client now uses web services for most of its features (OAB, OFF, Calendar, etc) when connecting to an Exchange 2007 server. One thing that might not be very apparent is that when an Outlook client makes it's connections it will check the Internet Explorer proxy settings of the Windows client via Windows API calls. If an Outlook clients IE proxy settings are pointing to an invalid or inaccessible proxy server it can cause connection problems.

One error you will see when the proxy settings are invalid when you are trying to download the OAB is the following error: 0x80190197.

C:\err 0x80190197
# for hex 0x80190197 / decimal -2145844841
BG_E_HTTP_ERROR_407 bitsmsg.h
# 1 matches found for "0x80190197"

The error being reported is an HTTP 407-Proxy Authentication issue.

Being that an Outlook 2007 client has the ability to download the OAB Version 4 via Web Distribution it can use BITS (Background Intelligent Transfer Service). For more information on BITS please see: http://www.microsoft.com/technet/community/en-us/management/bits_faq.mspx

Here is how the client works with proxy settings:

1. Outlook makes connection attempt.
2. Outlook will look for the proxy configuration script to determine what proxy settings should be used for the URL we are trying to connect to. 
3. If Outlook detects that there are no proxy settings are being used it will try to connect directly.
4. If there is a configuration script being used the Outlook client retrieves the proxy settings and tries to connect using those settings.
5. If Outlooks connection attempt fails, Outlook will not try a direct connection and you will get an error.

NOTE: When an Outlook client is using BITS 2.0 the Outlook client may also receive error code 0x80190197. This problem occurs when all the following conditions are true:

• The client program that is using BITS 2.0 does not specify that the credentials of the client can be used by calling the IBackgroundCopyJob2::SetCredentials method.
• The Microsoft LAN Manager compatibility level (LmCompatibilityLevel) on the BITS 2.0 client contains a value that is set to 1 or to 0. You can find the LAN Manager compatibility level entry on the following registry subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\LmCompatibilityLevel
• The file transfer is performed through a Windows-based server or a Windows-based Internet proxy server that requires Integrated Windows authentication.

How To Fix (Solution 1)

1. If you are using a GPO or IEAK, check the settings that are being pushed out to the clients.
2. Make sure that proxy server is up and available.
3. Make sure that Internet Explorer can connect to the URL that your Outlook client is attempting to connect too.

How To Fix (Solution 2)

Being that turing off the your proxy isn't an ideal solution, you can also add the following registry key to change the behavior instead. For more information please reference KB Article: 842309.

Thank to John Fullbright for his review on this article!!

Dave