Biometrics login / WebAuthn browser error

Problem statement

Some users got an error screen during biometrics login, which says

“Your identity could not be verified. This device doesn’t support the type of security key requested by this website”.

In our tenant logs, many instances of WebAuthn browser error in Auth0 logs appear to be related to the error screen during login.

Solution

The following will all generate a log with the description: "WebAuthn browser error"

  • If the user begins an enrolment for WebAuthn, and then clicks cancel
  • If the user has already enrolled but then attempts to use biometrics after clearing their browser data
  • If the user attempts to enroll more than one biometric authenticator for the same device + browser combo, for example, on two Macs both using Chrome - this is mentioned in the documented limitations:
    Configure WebAuthn with Device Biometrics for MFA

For the error “Your identity could not be verified. This device doesn’t support the type of security key requested by this website”, this appears to be an issue with the browser/OS not supporting webAuthn: