Whether you get nowhere or somewhere is irrelevant. If Face ID works for unlocking your phone and works for other apps except for one app then clearly the problem is with that app. Face ID for apps is managed by the app, not by Apple.
Now if Face ID doesn’t work for logging in, or has problems in other apps, that is more likely a problem with your phone or your Face ID setup.
I can think of 2 possible user errors that can cause Face ID (and other things) to fail for one app:
- If you are in the habit of force-closing apps by swiping up from the App Switcher screen that can cause the app to “forget” its settings, including the setting that saves your Face ID-enabled settings. In general you should never force-close any app unless it is not working.
- If you are using a VPN connection that can change your IP address randomly, so the app will think you are not using the same device and require login.