Your account has been configured for additional verification using the Azure Authenticator application for your smartphone ...

Your account has been configured for additional verification using the Azure Authenticator application for your smartphone or tablet.  Multi-factor authentication involves something you know (your username and password) and something you have (your mobile device).  When you sign on, you will continue to use the same username and password.  Before your sign on is complete, you will receive a notification from the Azure Authenticator application on your mobile device.  Simply launch the Azure Authenticator application and press the Authentication button to confirm your sign on.  If you don't confirm the sign on by pressing Authenticate, the sign on will be denied.

Note: You should only press the Authenticate button when you are actually signing on.  Otherwise, someone may be trying to sign on with your username and password, and you should report this potential fraud to your IT administrator.