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Outlook 2003/2007 clients cannot connect to Exchange 2010 server

brdlckhrt asked
I am transitioning from an Exchange 2003 server to an Exchange 2010 server.  I am able to send and receive email from a test account using OWA from the Exchange 2010 server. However, when configuring either an Outlook 2003 or 2007 client, I am not able to connect to the Exchange 2010 server. When configuring Outlook I get the username to resolve, but when I try to finish the configuration, at the very end a logon window appears wanting me to log onto the Exchange 2010 server? I shouldn’t be receiving this window, but even if I try to logon to the server using any account, administrator or otherwise, the logon window keeps showing back up? I have checked to make sure I am using encryption between the Outlook client and Exchange server but nothing is working.
Any help will be greatly appreciated.
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This is actually an easy fix.  In outlook, open the account properties, click on more settings, on the security tab, check the encrypt check box.


I have turned encryption on for both 2003/2007 clients. WIthout the encyption turned on I wasn't able to resolve the user name.


Outlook displays the message that it's Configuring Outlook Account and Creating Welcome Message when the server logon window appears.
Sorry, I misread.  This is happening with 03 as well as 07?  I have seen it with 07 and that is caused by certificate issues.  The send/receive when it does the GAL checks your certificate in 07.
Try this command from the Exchange Management Shell.

Get-MailboxDatabase  | fl.
Check for a parameter named RpcClientAccessServer.
See if it is pointing to the CAS Server.
If not you will have to set this value to look into the CAS Server.



I ran the command you suggested and the RpcClientAccessServer is pointed to the CAS server.
You can also disable the requirement of 2010 CAS servers to have encryption enabled by running
Set-RpcClientAccess –identity servername –EncryptionRequired $false.
This is not recommended though!

Testing purpose check it out and see if it works for you.


Also check for Windows Firewall on the Exchange 2010 and disable and check it out.
Try creating a test mailbox in Exchange 2010 and see if we are able to configure Outlook 2007 for it.
Is the Outlook 2007 Client that you are using within the Domain where you are attempting a MAPI connection.
Or else is it outside of the Domain where you are using Outlook Anywhere ie RPC/HTTP.

What  version  of Outlook 2007 do you have. If it does not have any Service Pack, then try adding the Service Pack 1 to Outlook 2007. It should work.


The firewall is turned off on the server.
The Outlook 2003/2007 clients are trying to connect  within the Domain.
The Outlook 2007 client is running SP2.
I haven't yet turned off encryption.
The email account I trying to send to on the new server is a test account.
What about a test Mailbox created in Exchange 2010? Does the Outlook not connect for the Test Mailbox as well.

Does your certificate match your internal domain?
I found out what the problem was. I had 1 test exchange account on the 2010 server that I was using (Test1). However, when testing the email account I would first log into the PC/domain with my domain user information, then configure Outllook to use the test account information. When I started to log into the PC/domain as the same user that I was trying to connect to the Exchange server then the login prompt went away.