Realme
Allow Unlimited Data for Specific Apps auf Realme
Data saving mode on Realme phones limits background data for apps that are not actively open. This lowers mobile data use, but it also delays notifications for apps that rely on a constant connection, such as messengers or mail clients.
WhatsApp is a common example. Without an exception, new messages or calls may only sync once you open the app, since the system pauses its background traffic to save data.
Adding an app to the exception list restores full data access for that app only, while Data saving mode keeps limiting everything else. This is the better option when you want to save data overall but still need instant delivery for one or two specific apps.
To manage the exceptions, open Settings ➔ SIM card & mobile data ➔ Data usage ➔ Data saving ➔ Apps with unlimited data usage. Find the app in the list and turn it on to remove its data restriction, or turn it off to put it back under the saving limit.
If Data saving mode causes more problems than it solves, turning it off completely is the simpler fix. Keep it enabled with select exceptions if you still want to reduce data use for less time-sensitive apps.

