TOTP in-band authentication
You can log in in-band with a valid TOTP OTP token code. This use case requires a QR code application such as IBM Verify, Google Authenticator, Duo Mobile, and so forth.
The device used to generate the TOTP token must set to automatically synchronize to the current time using a cellular or wifi connection. If this is not done, the time on the device may become incorrect over time causing generated TOTP tokens to be rejected.