Hi,
If you login to for example the following site: https://www.microsoft.com/en-us/learning/dashboard.aspx
you should see your MC ID in the upper right corner (see picture below)

The Authenticator app generates security codes you can use to help keep your Microsoft account secure. You can add your Microsoft account to the app by scanning a barcode or by manually entering a secret key.
The app implements industry-standard security code generation and may also work with other services and providers. You can learn more about keeping your Microsoft account secure at
https://account.live.com/p
It is possible that someone is trying to access your Microsoft account.
You may try resetting your Microsoft account password.
Please refer this article;
Get back into your Microsoft account if it's been compromised
http://windows.microsoft.com/en-us/windows/get-back-blocked-account
Hope this is helps!
Kind regards,
Leon
Blog:
https://thesystemcenterblog.com
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