You may not be able to sign in because of problems with your proxy settings or the DNS (Domain name server) cache. Confirm that you're connected to the Internet by visiting another website. If you are unable to connect to the Internet, you'll need to verify your Internet Explorer proxy configuration settings. Contact your ISP (Internet service provider. A company that provides access to the Internet) or network administrator (The person who manages a network of computers, and has the ability to change network settings and manage user accounts) to determine the correct settings. Once you're able to connect to the Internet, you can troubleshoot the DNS cache:
1. Make sure you can connect to Windows Live Messenger
1. Go to the MSN Web Messenger website and sign in. If you can sign in to MSN Web Messenger, but Windows Live Messenger still can't access the Internet, Windows Live Messenger may be blocked by a firewall.
2. Make sure your antivirus or antispyware programs don't conflict with Messenger.
2. If your computer is running Windows XP, clear the DNS resolver cache
* On the taskbar, click Start, and then click Run.
* Type cmd, and then click OK.
* At the command prompt, type ipconfig/flushdns, and then press ENTER.
3. If you're still unable to sign in to Messenger
1. If you use a dial-up connection and the connection is timing out, try to sign in again later.
2. If your computer is part of a corporate network, contact your network administrator to make sure that the network allows access to the Messenger service.
