You receive an error message when you try to use Windows Messenger 5.1 or earlier to connect to a computer that is running Office Live Communications Server (899152)


The information in this article applies to:

  • Microsoft Windows Messenger 4.0
  • Microsoft Windows Messenger 4.5
  • Microsoft Windows Messenger 4.6
  • Microsoft Windows Messenger 4.7
  • Microsoft Windows Messenger 5.0
  • Microsoft Windows Messenger 5.1

SYMPTOMS

When you try to use Microsoft Windows Messenger to connect to a computer that is running Microsoft Office Live Communications Server, the connection does not work. Additionally, you receive the following error message:
407 Proxy Authentication Required
This symptom occurs if the following conditions are true:
  • You are running Windows Messenger version 5.1 or earlier.
  • The Microsoft Internet Security and Acceleration (ISA) Server-based proxy computer does not use Basic authentication.

CAUSE

This problem occurs because Windows Messenger 5.1 and earlier do not support proxy authentication through an ISA Server-based computer that does not use Basic authentication.

WORKAROUND

To work around this problem, configure the ISA Server-based computer to use Basic authentication.
Modification Type:MinorLast Reviewed:9/16/2005
Keywords:kberrmsg kbAuthentication kbtshoot kbprb KB899152 kbAudITPRO
©2004 Microsoft Corporation. All rights reserved.