If all systems are stable and running, use the workaround procedure that is appropriate to your situation:
If you are on a home network, verify that all network cables are plugged in and that all network devices (such as hubs, cable or DSL routers, and residential firewall devices) are turned on and working properly. Verify also that other Internet programs (such as Web browsers) are working properly.
If you are connected to a corporate network, contact your network administrator.
If your network uses Microsoft Proxy Server 2.0 or Internet Security and Acceleration Server, verify that the Winsock Proxy Client version 2.0 or the ISA Firewall Client is installed properly:
On the taskbar, click the Start button, point to Settings, and then click Control Panel.
In Control Panel, look for an icon for WSP Client or Microsoft Firewall Client.
Double-click the icon for the appropriate client, and then click to select the Enable check box.
If your network does not use one of the Microsoft Proxy solutions, or if the network does not implement the Winsock Proxy features of the programs, you may be using an HTTP Proxy server. Verify that the proxy settings are entered correctly in MSN Messenger Service Client:
On the Tools menu, click Options.
Click the Connection tab, and then click to select the I use a proxy server check box.
In the Type box, click HTTP Proxy.
In the Server and Port boxes, type the name or address and port of your HTTP Proxy server.
Microsoft Windows Messenger 4.0, Microsoft Windows Messenger 4.5, Microsoft Windows XP Home Edition, Microsoft Windows XP Professional, Microsoft Windows XP Professional x64 Edition, Microsoft Windows Messenger 4.6