The subject behavior will occur if you attempt to connect to the Microsoft Office Live Communications Server 2003 through any of the following:
- A Network Address Translation (NAT) device.
- A firewall device.
- A proxy device.
To workaround this issue, on the Windows Server 2003 computer:
01. Install a computer certificate on the Live Communications Server Home Server computer. See Request a certificate in the Windows Server 2003 Help and Support Center.
02. Start the Live Communications Server utility.
03. Expand Servers.
04. Right-click the Home Server that you want to configure and press Properties.
05. Select the Connections tab.
06. Press Add.
07. Select TLS (Transport Layer Security) in the Transport type list and press Change Certificate. If you have multiple Home Servers, leave the Authenticate remote server (TLS Mutual) box checked.
08. In the Select Certificate dialog, select the computer certificate that you want to use and press OK.
09. Verify that 5061 appears in the Listen on this port box.
10. Press OK and OK.
On the client computer:
1. start Windows Messenger.
2. Press Options on the Tools menu.
3. Select the Accounts tab.
4. Press Advanced under SIP Communications Service Account.
5. Select Configure settings.
6. Select TLS and type the fully qualified domain name of the Live Communications Server Home Server into the Server name or IP address box.
7. Press OK and OK.
8. If you receive The changes you have made to your sign-in information won't take effect until the next time you sign in, press OK.
9. Sign out of Windows Messenger and sign back in.
NOTE: See the Configuring a Home Server and Windows Messenger for TLS section of the Microsoft Office Live Communications Server 2003 Deployment Guide in the Documentation folder of the Microsoft Office Live Communications Server CD-ROM.