AUTHENTICATION BY CALL TO PHONE
How to setup two-factor authentication by a call to a phone number.
ON YOUR COMPUTER
1. Go to https://account.activedirectory.windowsazure.com/Proofup.aspx
2. In the drop down box under "What's your preferred option?", select Call my authentication phone.
3. If needed, set the Country or Region code to "United States"
4. Enter an authentication phone number (that is, the phone number you want to be called to authenticate your logon).
5. Select Save.
Note: When you login and two-factor authentication is required, you will receive a phone call and you will be asked to press # on your phone to authenticate.