My scenario, I have 2 Mailbox server with CCR cluster running on Windows 2008, 2 HUB/CAS server configured with unicast NLB and1 Edge Server with all server updated with Exchange Rollup 5. I configured Autodiscovery in my enviornment. Autodiscovery is working fine. When I login in Office 2007 on lan it prompts me password for thrice& it authenticate to Cas Node 1 or Cas Node 2 not to Clustered Mailbox which is unexpected.In Outlook 2003, It's properly login Clustered mailbox also outlook anywhere is working fine.So please suggest me why authentication goes to HUB/CAS server not to mailbox server whenI logs to Office 2007 that is problem which I am facing.Please help to solve this problem

hi,can you disjoin client from domain and re join it again.try oultook to connectagain.regards,Exchange - MVP | www.cozumpark.com | www.mumincicek.com

Hi, That is normal. When logining Outlook 2007, it will contact Autodiscover service which running in CAS to retrieve the relevant settings, such as availability, OAB and so on. That needs the authentication to be handled on the CAS. For Outlook 2003, that is because autodiscover is not integrated with it. Thus, now please check whether the Integrated Windows authentication and Basic authentication have been checked on the Autodiscover virtual directory under IIS. If not, please check them. Moreover, ensure "Integrated Windows Authentication" is checked on the EWS virtual directory, then restart IIS and check this issue. Thanks Allen