To get call logs data, Telephone(Call) permission must be granted to SafeMinor application on your child's device.
Make sure this permission is granted to SafeMinor app. If not, then grant permission.
To check app permissions:
1. On your device, open the main Settings app.
2. Tap Apps or Application Manager (depending on your device, this may look different).
3. Tap on the SafeMinor app.
4. Tap Permissions. If a permission is turned off, the switch next to it will be gray.
5. Turn all permission on.6. Try using the app again.