If you are having problems connecting to the service, try re-typing your name in the Sign In dialog box. Although some sign-in names are case-sensitive, some are not. If you have trouble signing on, type your sign-in name exactly the way it was when you applied for it.
If your Passport is not recognized, try going to a Passport site (www.passport.com or www.hotmail.com) to make sure you are recognized there. If so, the messaging servers could be temporarily down. Wait a short while and then try again.
Make sure that the I use a proxy server check box is clear on the Connection tab (on the Tools menu, click Options, and then click the Connection tab). Only certain proxy servers require this, so unless you have been told to select this by your network administrator, do not do so