Go to Settings > Security and lock screen > Find the Face recognition and enable Show notifications.
After waking up the screen, notifications will only be shown on the lock screen when the device detects the correct registered face.
If the phone cannot detect the correct registered face, no notifications will appear.
Note: The operation steps/information in this FAQ may not be applicable to all types/series of Zenfone product. Some options in the screenshots and operating procedures may slightly vary, depending on the software and firmware version.