Despite what it says, everything looks OK my end using outlook.com
Lots of the staff here cant login, But if they where all ready logged in then it is fine. :(
They've been having problems with the Account Authentication services recently..
I first saw it on Sunday night, on Xbox.com..
Hopefully its just to do with the work they've got in progress before the new user agreements come into force.
Got to say though, Microsoft's turnaround and online status feedback is brilliant. Easy to understand and no silly support queries to raise :)
Going ok for my personal account but we were having some problems with Live@Edu during the day......
Live@edu has a service health dashboard: https://status.eduadmin.live.com/
If you sign in as an administrator you can find out more information.