Android can stop apps that run in the background to save battery. If Notification Tracker is stopped, notifications arriving at that time may not be saved and alarms can't ring.
Steps
- Open Settings > General Settings.
- Find Background activity. The status shows Allowed or Not allowed.
- Tap the row and choose Allow in the Android dialog.
- On Samsung phones, also remove the app from sleeping apps (see "How to fix Samsung sleeping apps").
- On Xiaomi, Huawei, Oppo, Realme and Vivo, also turn on Autostart for the app.
Tips
- This is a phone setting, not a bug in the app.
- If your phone stopped the app, the app can show a message in History with the time it happened and a Fix button.