The thing has been down a couple of times for me lately. It came back up after a while.If not:
This is from the help section in mine,maybe it will help.
Ask yourself these questions:
Do you have a .NET Passport? You must have a Microsoft .NET Passport to use Windows Messenger. A Passport gives you a single, secure way to sign in to multiple Internet sites and services using one sign-in name and password.
As a Windows XP user, you probably have a Passport, but if not, you can get a Passport using the .NET Passport Wizard in Windows XP (Start, Control Panel, User Accounts, Advanced tab).
Have you typed your name and password correctly? Some sign-in names are case-sensitive, and some are not. If you have trouble signing in, type your sign-in name exactly the way it was when you applied for it. Also, be sure you type your password correctly because all passwords are case-sensitive.
Have you used the correct password? If you are unsure of your password, you can go to the Passport site and get a new one.
Is your Passport working? If your Passport is not recognized, try going to a Passport site (
www.passport.com or
www.hotmail.com). Sign in, and make sure you are recognized there. If so, your messaging server could be temporarily down. You can check its status on the .NET Service Status page.
Are you using Windows Messenger behind a corporate firewall? If you are not behind a firewall but use an Internet service provider instead, make sure that the I use a proxy server check box is clear on the Connection tab (Tools, Options). If you are behind a firewall, verify with your network administrator that the information you have on the Connection tab of the Options dialog box is correct (Tools, Options).