I am trying to connect Outlook 2007 to Exchange (Hosted Exchange from Rackspace). Soon, I will need to roll this out for our entire office. With the Exchange account added to Outlook, Outlook starts up and asks for the user's username and password. Unfortunately, it doesn't like the password I use for it. I can confirm this username (email address) and password combo works by using Outlook WebMail, and another user (in another network/office) confirmed the Exchange account does work within his Outlook client. In my network/office, I can confirm that an Outlook 2007 client (under Windows 7) can connect to the Hosted Exchange server from Rackspace.

However, I have not been able to get Outlook 2007 (under Windows XP SP3) to connect to the very same Exchange server Outlook 2007 (under Windows 7) can connect to. Outlook continuously prompts me for the username and password and does not accept the correct combination.

Now, regarding the Outlook client that cannot connect/login to Exchange:

• The user has full admin rights on the workstation
• We do not run a domain controller/LDAP
• The firewall on the workstation has been disabled
• Real time file scanning in Microsoft Security Essentials has been disabled
• There are no virus scanning applications that would interface with Outlook or an email server.
• The Exchange account is setup to run on a newly created Outlook profile
• The network firewall does not log any blocked attempts
• A packet capture at the router reveals communication between the workstation and the Exchange server or proxy (though, this is SSL encrypted, so I don't know what the computers are saying)
• I have applied a fix (Added DWORD value of 0 for DefConnectOpts under HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\RPC) that was recommended to make RPC function when the workstation does not have a default gateway set. Workstation is configured as DHCP. This fix did nothing, and it may be worth noting the RPC subkey was not present until I added it.
• RPC service is running on the workstation
• The program is not running under any compatibility mode. Side note: Outlook 2007 installs with compatibility mode for XP enabled by default in windows 7. Outlook 2007 will not even try to connect to exchange if this compatibility mode is checked. In windows xp, I tried checking compatibility mode for windows 2000, and was unable to connect to exchange as well.

Here is the specific configuration I've used in a blank outlook profile:

Microsoft Exchange Server: ##MASKED##-MBX-C18.mex07a.mlsrvr.com
Username: (Full Email Address: [email protected])
Password: ##MASKED##
Outlook Anywhere: Connect to Microsoft Exchange using HTTP
Exchange Proxy Settings:
Proxy Server: mex07a.emailsrvr.com
Check "Connect using SSL only"
Under "Only connect to proxy servers...", enter: msstd:mex07a.emailsrvr.com
Check "On fast networks, connect using HTTP first, then connect using TCP/IP"
Check "On slow networks, connect using HTTP first, then connect using TCP/IP"
Proxy authentication settings: Basic Authentication

Notes: mex07a.mlsrvr.com and mex07a.emailsrvr.com may look incorrect at first glance, but this is not a typo - these instructions were handed down from rackspace and are confirmed to be working, just not on this workstation.

I have tried to use the RpcPing utility but must have been using it wrong. I got as far as "Bad Interface Descriptor". It would seem to me getting Outlook and Exchange to work together would be a breeze, especially since everything is done over port 80 with web services. Unfortunately, the user is stuck with WebMail access only, because Outlook won't accept the Exchange credentials.

Do you have any ideas of other things I could try to debug this issue further? Any and all help is greatly appreciated. Thank you!

-Chris