https://www.pingidentity.com/en/resources/blog/post/what-is-out-of-band-authentication-ooba.html
What is Out-of-Band Authentication (OOBA)? | Ping Identity
Learn about out-of-band authentication (OOBA) and its role in two-factor authentication (2FA) and multi-factor authentication (MFA).
out of band authenticationwhat isoobapingidentity