Today I got notifications from Live mail that my account needed to be re-authenticated for some reason and that I should re-enter my password. I didn't trust what was going on so I changed my password. After that was done I got another of the same notification, and my new password didn't work. Only after about five attempts did it accept my new password and log me in. When I tried to change the password for my account on my phone's e-mail client, the new password was not accepted, nor does the old password work. 

I'm extremely confused by this and I'm worried Live mail might lock me out of my account again at any moment. Does anyone know what's going on here?

It might be that today I've sent about a dozen nearly-identical e-mails to participants in a scientific study and Microsoft interprets this as spamming. But that's never happened to me before. What's the deal here?