Consider the following scenario: 
- In Microsoft Internet Security and Acceleration (ISA) Server 2006 with Service Pack 1 (SP1), you publish a Microsoft Exchange Server 2003-based server.
- When you publish the Exchange server, you select the Outlook RPC/HTTP(s) option.
- On an external computer, a user tries to connect to the Exchange server by using Microsoft Office Outlook.
Note When an external computer uses Outlook to connect to an Exchange server through RPC, the external computer is called an Outlook Anywhere client. - On the Outlook Anywhere client, the user provides the wrong user name or the wrong password.
In this scenario, the Outlook Anywhere client continually uses the wrong credentials every time that it tries to authenticate itself on the Exchange server. The user is not prompted to enter the correct credentials. Additionally, if the Account Lockout policy is implemented in Active Directory, the user account eventually becomes locked out.
Check out:
http://support.microsoft.com/kb/956192/en-us
for the solution and a fix.
HTH,
Tom
Thomas W Shinder, M.D., MCSE
Sr. Consultant / Technical Writer
Prowess Consulting www.prowessconsulting.com
PROWESS CONSULTING | Microsoft Forefront Security Specialist
Email: [email protected]
MVP — Forefront Edge Security (ISA/TMG/IAG)