To receive one-time lockout codes via SMS, you need to confirm your mobile number as capable of receiving SMSes from us. (SMS lockout codes are not available in all countries / mobile networks.) Set up SMS lockout codes. You should enter your phone number with its international country code first. (The United States is +1.)
Please note that setup is not complete until you enter the confirmation code we send you via SMS on the web.
If you lose or reset your smartphone, you can request your SMS lockout code after entering your password, by clicking the link "Request a one-time lockout code." This link is only available if you've set up SMS lockout codes!
Once you've set up lockout codes, you need to set up two-step verification for your account. Primary two-step verification uses time based one time passwords, and requires an app on your computer or smartphone, or a hardware token.