Guide
If the app gets "killed" in the background, call notifications stop arriving or callback reminders fire late — the cause is almost never the app itself, but aggressive battery saving and blocked auto-start. Many Android makers put third-party apps to sleep by default. Below is what you need to enable, plus separate step-by-step guides for your brand.
In short: the app needs three things — to run in the background without battery limits, to start automatically, and to schedule exact alarms. Where exactly you enable this depends on the manufacturer. Pick your brand below.
The most common cause: battery optimization puts the app to sleep once the screen is off, and notifications stop arriving. In the app settings choose Unrestricted (or "Don't optimize") so the system won't evict it from memory in the background.
On many phones (Xiaomi, Realme, Oppo, Vivo, Huawei, Honor, Tecno) third-party apps are blocked from auto-start by default. As a result the app doesn't start after a reboot and gets killed when memory is cleared. Enable auto-start and background activity manually — and it helps to "lock" the app card in Recents so the clear button doesn't sweep it away.
Callback reminders rely on exact alarms. On Android 12 and newer they need the separate "Alarms & reminders" permission, and on Android 13+ the notification permission too. Without them a reminder may fire late or not at all.
FAQ
Most often the system evicted the app from memory to save battery. Turn off battery optimization for the app (Unrestricted) and allow auto-start — after that notifications will arrive reliably.
Check the "Alarms & reminders" permission (Android 12+) and make sure the app is excluded from battery optimization. On Xiaomi, Huawei and Honor also enable auto-start — without it the alarm can be put to sleep.
No. On "clean" Android (Google Pixel, Motorola, Nokia, Sony) turning off battery optimization once is usually enough. Extra steps are needed on phones with custom skins — Xiaomi, Samsung, Realme, Oppo, Vivo, Huawei, Honor, Tecno.
The drain is minimal: the app doesn't run constantly — it just receives notifications and shows reminders on time. These permissions only stop the system from killing it at the wrong moment.
