Oppo
Set Network Permissions per App auf Oppo
On Oppo phones running Coloros, every app is allowed to use both mobile data and WLAN by default. This is controlled by the system's Network permissions list, a per-app setting that decides whether an app can go online over WLAN only, mobile data only, both, or neither.
If an app keeps consuming mobile data in the background, or fails to load content while you are away from a WLAN network, this setting is usually the reason. Restricting an app to WLAN only saves mobile data but stops it from working outside WLAN range. Restricting it to mobile data only can break the app whenever you are connected to WLAN, since it will simply be blocked from going online.
To change the permission, go to Tap on Settings ➔ Tap on SIM card & mobile data ➔ Tap on Data usage ➔ Tap on Network permissions ➔ Choose an App ➔ Choose an option. Pick the app you want to adjust, then select the access level that fits how you use it.
If an app misbehaves even after this change, check whether background data or battery optimization for that app is also limiting its connection, since those are separate settings.