Samsung
Allow Apps to Use Data While Data Saver Is On auf Samsung
Data saver is a system-wide function on Samsung phones that restricts background mobile data for almost every app once it is turned on. It reduces data usage across the device, but it also stops messaging apps, mail clients or navigation tools from syncing unless they are opened directly.
Whitelisting an app inside Data saver settings removes that restriction just for the selected app, while every other app stays limited. This is the correct fix when specific apps miss notifications, delay messages or fail to update in the background, but mobile data usage overall should stay controlled.
Menu path to allow an app
Open Tap on Settings ➔ Tap on Connections ➔ Tap on Data usage ➔ Tap on Data saver ➔ Tap on Allowed to use data while Data saver is on ➔ Turn On/Off one or more Apps.
Toggle the switch next to each app you want to exempt. Apps left off remain blocked from background mobile data as long as Data saver stays enabled.
If notifications are missing across almost every app, check whether Data saver is disabled entirely instead of whitelisting single apps, since that points to a broader background-restriction issue rather than one specific app.
Whitelisting an app increases its mobile data usage in the background, so only allow apps you actually need reachable without Wi-Fi.