Event ID 46 for OWA CAS proxy really attempts to discuss two separate topologies as shown below. When CAS1 is the Internet facing CAS, you can manually copy the resource folder from CAS2 to CAS1 to resolve this issue. After copying the resource folder, you will need to restart the MSExchangeServicesAppPool.
When CAS2 is the Internet facing CAS, your only recourse is to install the matching rollup on CAS2 or uninstall all higher versions of rollups on CAS1.
Here’s the original language of Event ID 46 for both scenarios.
Log Name: Application
Source: MSExchange OWA
Date: <timestamp> PM
Event ID: 46
Task Category: Proxy
To ensure reliable interoperability, the proxying Client Access server needs to be running a newer version of Exchange than the Client Access server it is proxying to. If the proxying Client Access server is running a newer version of Exchange than the Client Access server it is proxying to, the proxying Client Access server needs to have an Outlook Web Access resource folder (for example, "<Exchange Server installation path>)\ClientAccess\owa\8.0.498.0" that contains all the same versioned resource files as the Client Access server it is proxying to. If you will be running Outlook Web Access proxying with mismatched server versions, you can manually copy this resource folder to the proxying Client Access server.
The typical installation of Exchange 2007 includes the CAS, MBX and HUB roles. Entourage requires little if any server configuration to connect in this topology.
However, once these roles are separated, there’s a few additional steps to take.
One thing to note – you do not need to install the latest WebDAV component from the IIS team in order to get Entourage to work with Exchange 2007 on Windows 2008 server. If you’ve already installed the component:
http://learn.iis.net/page.aspx/350/installing-and-configuring-webdav-on-iis-70/ I've included steps below to uninstall it. However, with the new Entourage 2008 Web Services Edition free upgrade, I would highly recommend upgrading your Entourage clients than continue to support WebDAV. http://download.microsoft.com/download/2/0/C/20C4D3D0-C2B1-44F5-94B5-322BE47616D8/EWS-1305-EN.dmg
If you still require WebDAV version of Entourage in your environment though, here's what you'll need to do to get things right. On the Exchange 2007 server the IIS WebDAV component is installed:
1) Stop the W3svc service [this usually prevents the need to reboot] net stop w3svc
2) Uninstall the WebDAV component from Control Panel, Programs and Features
3) Start the W3svc service net start w3svc
4) run the following commands from the Exchange Management Shell
Remove-OwaVirtualDirectory "exchange (default web site)"
-Refresh IIS manager to ensure the exchange virtual directory has been removed
New-OwaVirtualDirectory "exchange" -OwaVersion Exchange2003or2000 -VirtualDirectoryType Mailboxes -WebSiteName "Default Web Site"
5) Ensure the proper permissions are configured on the Exchange virtual directory:
CAS role == Basic
MBX role == Windows Auth [as well as SSL settings with Require SSL unchecked]
6) Run iisreset /noforce
The steps above show the basic setup requirements for Entourage:
On the CAS, the /Exchange virtual directory needs to have Basic authentication,
On the MBX, the /Exchange virtual directory needs to have Windows Auth enabled and the SSL requirement unchecked.
A great troubleshooting step from here is to enable Forms Based Authentication on the CAS for the OWA virtual directory in Exchange Management Console. Once that is enabled, if you see redirection working properly for OWA through your browser, then most likely your server is configured correctly.
For example, for Entourage to work, you need to be able to access https://CAS/exchange from the Apple client you want to run Entourage from [which after getting redirected to the OWA FBA page you should be able to log in]. From the CAS, you should also be able to access http://MBX/exchange - If these two tests work, then you most likely need to visit
931350 You cannot connect to your mailbox on Exchange Server when you use Entourage for Mac
It’s better to work from https://CAS/exchange to http://MBX/exchange - if connecting to the CAS won’t work, then connecting the MBX over the Exchange virtual directory won’t work either.