Mozilla Firefox's WebAuthn implementation currently does not allow Password Manager browser extensions (Bitwarden, Proton Pass, etc.) to intercept passkey prompts the way Chromium-based browsers do. When a site requests a passkey, Firefox routes the request directly to the OS-level authenticator (e.g. Windows' built-in FIDO/Hello prompt), bypassing the extension entirely. Switching to a different browser (Chrome, Edge, Brave, or Opera) should resolve the issue.
Please Note
- Since the Firefox limitation might be addressed in future releases of the browser, we recommend you, in any case, to test the Passkey authentication with the most recent version of the Firefox browser and of the browser extension.