have you been connecting at school, or are you in the process of setting things up? If you have been connecting previously, do as Malthus says. In the mean time, go ahead and make doubly sure any (auto-)connect features your FE has are using the correct accountname and password.

If you are just now setting up your computer or something changed on your school network that requires you to modify your connection, chances are you are not locked out and simply have something wrong in the connection properties that is causing a timeout (this is different than an incorrect login and should not in any way be setting off the 12-hour alarm).
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