Why does this happen?
It's not a bug — it's your phone trying to save battery.
Android phones can restrict what apps are allowed to do while they're not open, to make the battery last longer. RebootMonitor needs to check your device's status once a day in the background. If your phone restricts it too much, that daily check can be delayed — sometimes by several days.
Good news: fixing it takes less than a minute, and RebootMonitor still uses almost no battery either way — this setting just controls how strictly your phone limits it.
Open the gear icon
Open RebootMonitor. In the top right corner, next to the app name, tap the gear (⚙) icon.
Look for the yellow card
If your phone could delay reminders, you'll see a yellow card at the top that says "Reminders may be delayed."
If you don't see this card, your phone already allows RebootMonitor to run normally — nothing to do!
Tap the card
Tap anywhere on the yellow card. This opens your phone's own battery settings screen for RebootMonitor — it's a standard Android screen, not part of the app.
You'll see RebootMonitor listed with a switch next to it.
4Turn the switch off
Switch it off (or choose "Allow" / "Unrestricted" / "Don't optimize" — the exact words depend on your phone's brand). That's it. Reminders will now arrive on time.
Phone brands word this differently. Samsung calls it "Optimise battery usage"; other phones say "Allow background activity," "Unrestricted," or "No restrictions." Whatever the wording, you're looking for the option that means RebootMonitor is not limited.
That's it — you're done
Go back into RebootMonitor's settings and the yellow card will be gone. Your reminders will now arrive right on schedule.