Guides / Daybreak

Alarm not ringing on Android? Here's why, and how to fix it

Updated 4 November 2026 · Provantic Technologies

Most missed alarms come from battery savers that stop the alarm app in the background, a restart that cleared the alarm, or alarm volume set too low. Exclude your alarm app from battery optimisation, allow it to start automatically, and test it with the phone locked.

The usual causes

• Battery optimisation stops apps in the background, including alarm apps. Phones from Xiaomi, Redmi, Oppo, Realme, Vivo, OnePlus and Samsung are aggressive about this.
• Autostart is off, so after a restart the alarm app can't re-arm itself.
• The phone restarted overnight, for an update or a low battery.
• Alarm volume is low or muted, separately from ringtone volume.
• The app was swiped away and the phone treats that as "stop this app".

Fixes that work on most phones

1. Set your alarm app's battery use to Unrestricted or No restrictions (Settings › Apps › your alarm app › Battery).
2. On Xiaomi, Redmi, Oppo, Realme and Vivo, turn on Autostart for the alarm app.
3. On Samsung, add the app to Never sleeping apps in Battery settings.
4. Check alarm volume (not just ringtone) in Sound settings.
5. Set a test alarm two minutes ahead, lock the phone, and wait.

Menu names change between phone models and Android versions; search your Settings for "battery", "autostart" or "sleeping apps".

An alarm built for this

Daybreak uses Android's strongest alarm timer, rings through silent mode and Do Not Disturb, re-arms after a restart even before you unlock, and walks you through these battery settings for your phone's brand. Every evening at 9 PM it warns you if something could stop tomorrow's alarm.

Questions