Article ID: 2423079 - View products that this article applies to.
Consider the following scenario:
Note If the downstream server is running ISA Server 2006, this issue does not occur.
This issue occurs because of an error in the downstream server after the upstream server sends an NTLM challenge.
Update informationTo resolve this issue, install the software update that is described in the following Microsoft Knowledge Base (KB) article:
(http://support.microsoft.com/kb/981324/ )Software Update 1 for Microsoft Forefront Threat Management Gateway (TMG) 2010 Service Pack 1
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/824684/ )Description of the standard terminology that is used to describe Microsoft software updates