Once you create AWS you should activate “Activate MFA on your root account” 

and do that you should use your phone (Iphone, Android) download google authenticator app from the app store/Google Play once the installation is done Scan the QR and Enter the code, the code will be change automatically, if the first try not working and you receive this error ” failed to associate the token” uninstall the app and try again.

Thank you
Osama