You cannot connect to a Live Communications Server 2005 pool, and you receive an error message


SYMPTOMS
After you enable a user for live communications to a Microsoft Office Live Communications Server 2005 pool, that user cannot sign in to the session initiation protocol (SIP) communications service. If the user tries to sign in, the user receives the following error message:

Signing in to SIP Communications Service failed because the sign-in name, username, or password is incorrect, or the authentication service is not compatible with this version of the program. If you have signed in correctly and the problem persists, contact your network administrator.

However, if either of the following conditions is true, the user can sign in successfully:

? You configure the user account to connect to a Live Communications Server 2005 Standard Edition server.
? You configure the user account to connect to a Microsoft Office Live Communications Server 2003 Home Server.

CAUSE
This issue occurs if the following conditions are true: ? The user tries to connect to the SIP communications service from a computer that is running Microsoft Windows Messenger 5.0.
? Windows Messenger 5.0 is configured to connect to the Live Communications Server 2005 pool by using TCP.

WORKAROUND
To work around this issue, use one of the following methods.
Method 1: Upgrade to Windows Messenger 5.1
Upgrade the Windows Messenger client program to Windows Messenger 5.1. This issue does not occur with Windows Messenger 5.1. To obtain the latest version of Windows Messenger, visit the following Microsoft Web site:
http://www.microsoft.com/windows/messenger

Method 2: Use Transport Layer Security (TLS)
Configure Live Communications Server 2005 to accept connections by using TLS. For additional information about how to configure TLS in Live Communications Server 2005, see the Live Communications Server 2005 Enterprise Edition Deployment Guide. To obtain this guide, visit the following Microsoft Web site:

http://www.microsoft.com/downloads/details...&displaylang=en

MORE INFORMATION
The Live Communications Server 2005 Enterprise Edition Deployment Guide is available as part of the Live Communications Server 2005 Deployment Resources. To obtain these deployment resources, visit the following Microsoft Web site:
http://office.microsoft.com/en-us/FX011526591033.aspx

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APPLIES TO
? Microsoft Windows Messenger 5.0
? Microsoft Office Live Communications Server 2005 Enterprise Edition