Hello, After applying a group policy security configuration to harden my 2008 domain controller my Outlook 2010 clients started prompting for a username and password. Can anyone give me recommendations I how to troubleshoot this? My enviroment is: Outlook 2010 clients 1 Exchange sp1 server 2 domain controllers (1 Windows 2003 and 1 Windows 2008)

What Group Policy Setting is that ? You can Try changing authentication setting in Outlook - Negotiate authentication or BasicSatheshwaran Manoharan | Exchange 2003/2007/2010 | Blog:http://www.careexchange.in | Please mark it as an answer if it really helps you

We are goverment contractors who are required to harden our servers with a secure configuration. It is very simaliar to the WS08-SSLF-Domain-Controller policy. Is there any tools that I can run which will tell me why authentication is not working?

Hi there, What version Exchange server is there? If it is Exchange 2007, we may try to specific a GC for Outlook clients. Refer to: http://support.microsoft.com/kb/319206 Hope it is helpful.Fiona Liao TechNet Community Support

Hello, Its Exchange 2007 sp1. Instead of making changes to the Outclient I would like to find out what is causing the problem in the secure configuration. Is there any tools or diagnostics I can run?

Can you check Default Domain Policy under Windows Settings > Security Settings > Local Policies > User Rights Assignment, the policy Manage auditing and security log and see if the Exchange servers are still there?James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

I'd firstly suggest apply the latest update on the Exchange server. See http://technet.microsoft.com/en-us/library/ee221180(EXCHG.80).aspx. We may verify the application event log in the GC server as well as the Exchange servers. Meanwhile, I'd suggest you also post this issue in AD forum since the issue occurs after applying the GP. Hope it is helpful. Fiona Liao TechNet Community Support

Hello, have you applied the update KB2553248 to the clients? If yes try to uninstall it and then try again. Greetings, Toni

Hello metter2369, Is there any update?Fiona Liao TechNet Community Support

Hello, Im closing this out and going to post it to the AD forum as suggested. Thanks for all your help. Mark