Oppo
Enable Face Recognition for App Lock and Private Safe auf Oppo
Oppo phones store one face profile under Coloros and let several security features reuse it. By default, only the lock screen is linked to that profile. App Lock and Private Safe each need their own permission before they accept your face instead of a password or pattern.
This separation exists so a shared device does not automatically unlock protected apps just because someone unlocked the screen with their face. It also matters if you switch phones between family members and want different apps to stay password protected.
To turn face recognition on for these extra areas, open Settings ➔ Password & biometrics ➔ Face ➔ Use face for. From there you can switch on the option for App Lock, Private Safe, or both, alongside the existing screen unlock toggle.
If face recognition still asks for a password after enabling this, check that lighting is even and that no case or accessory blocks the front camera. In low light or with major appearance changes, re-registering your face under the same menu often solves recognition failures faster than adjusting individual app settings.