Today I hit a very strange problem with a customer environment
We deployed Exchange 2010 SP3 with Outlook Anywhere using internal Certificates from internal Authority.
We use reverse proxy and CAS array for publishing the services.
We did intensive test with Windows 7 clients and Outlook 2007/2010 . There were some configuration issues that we fixed in the process of the deployment but everything was working fine ,and Outlook Anywhere , ActiveSync are working without any problems.
Recently we tried to connect with Windows XP client but we receive constant prompt for authentication and Outlook is not connecting to the CAS Array servers.
I triple check Root CA , Certificates , Configuration , autodiscover config and so on . Still receive the prompt again and again.
I create a test environment that is very simple just to test RPC over HTTP without CAS array and Reverse proxy with Windows XP
I keep getting the same prompt ,but when I test with Windows 7 machine everything is fine and Outlook is connected.
My test configuration is like this:
Windows Server 2008 R2 Sp1 with DC role , certification authority and Exchange Server 2010 Sp3.
autodiscover.domain.com points to DC (exchange server)
email.domain.com points to DC(Exchange server)
InternalURL and external(autodiscover ) https://autodiscover.domain.com/autodiscover/autodiscover.xml
EWS internal and external https://email.domain.com/EWS/Exchange.asmx
CAS Server : exchange.domain.local
Outlook Anywhere - NTLM
Outlook Anywhere FQDN: email.domain.com
One certificate with two SAN : autodiscover.domain.com and email.domain.com
Certificates and autodiscover is working fine in Windows XP . When I try to connect I get the prompt constantly .At the same time Windows 7 machine is connected using RPC over HTTPS without error
I tried to set EXPR certificate principle name to msstd:email.domain.com but the problem persist.
I'm out of ideas . Based on my other Exchange 2010 Sp2 implementations there were no such problems.
To summarize : Windows 7 and Outlook 2007/2010 is connecting to Exchange 2010 Sp3
Windows XP and Outlook 2007/2010 can't connect to Exchange 2010 Sp3