Android Notifications Delayed or Not Showing - How to Fix

A message sent at 9am appears at 2pm. Or it does not appear at all until you open the app, at which point ten notifications land at once. Wi-Fi is fine, mobile data is fine, the app works perfectly when you are looking at it.

This is not a network problem. It is Android deciding that the app does not deserve to run in the background, and it has been getting more aggressive with every release. Manufacturers then layer their own restrictions on top, which is why the same app is reliable on a Pixel and useless on a Xiaomi.

How Android notifications are supposed to work

Understanding the mechanism makes the fixes obvious.

Most apps do not poll a server. They register with Firebase Cloud Messaging, Google’s push service, which maintains one persistent connection on behalf of every app on the phone. When a message arrives, FCM wakes the target app’s process and hands it the payload. The app then posts the notification.

Two things can break this:

1. The app’s process is not allowed to be woken — a battery restriction.
2. The app is woken and posts the notification, but the system or a mode suppresses the display — a permission or Do Not Disturb issue.

Delay points to the first. Total silence points to the second.

Fix 1 - Battery optimisation

This is the cause in the clear majority of cases.

Go to Settings → Apps → [app] → Battery (on Samsung it is Settings → Apps → [app] → Battery, on Pixel Settings → Apps → [app] → App battery usage).

You get three options:

Set every app you actually care about to Unrestricted. The battery cost of doing this for five or six apps is small — a few percent a day at most — and it is the difference between a messaging app working and not.

Adaptive Battery

Settings → Battery → Adaptive Battery learns your usage and restricts apps you open rarely. The failure mode is specific: an app you use once a week but need alerts from daily gets categorised as unimportant and throttled.

Turning Adaptive Battery off entirely is reasonable if notifications matter more to you than the last few percent of battery life. Alternatively, set the affected apps to Unrestricted, which exempts them.

Fix 2 - Brand-specific background limits

Stock Android’s restrictions are only half the story on most phones.

Samsung

Two settings cause most Samsung notification complaints:

• Settings → Battery → Background usage limits → Put unused apps to sleep. Turn this off. It force-sleeps anything you have not opened in a few days.
• Deep sleeping apps and Sleeping apps on the same screen. Open each list and remove any app you need notifications from. Apps in Deep sleeping never run in the background at all.

Also check Settings → Device care → Auto optimisation and disable Close apps that are not in use.

Xiaomi, Redmi and POCO (MIUI / HyperOS)

The most restrictive of the major brands. Three separate settings must all be correct:

1. Settings → Apps → Manage apps → [app] → Autostart — turn on. Without this the app cannot start after a reboot or after being killed.
2. On the same screen, Battery saver → set to No restrictions.
3. Open Recents, pull down on the app’s card, and tap the lock icon. This stops memory cleanup from killing it.

OnePlus and Oppo (OxygenOS / ColorOS)

• Settings → Battery → Battery optimisation → [app] → Don’t optimise.
• Settings → Apps → [app] → Battery usage → Allow background activity and Allow auto-launch.
• Turn off Settings → Battery → Advanced → Sleep standby optimisation.

Huawei

Settings → Battery → App launch → switch the app to Manage manually and enable all three toggles (Auto-launch, Secondary launch, Run in background).

Fix 3 - Notification permissions

From Android 13, notifications are a runtime permission. An app must ask, and you must grant it. Deny the prompt — or dismiss it accidentally — and the app goes permanently silent with no other symptom.

Check Settings → Apps → [app] → Notifications. The master toggle must be on.

Below it, apps declare notification channels — separate categories like Messages, Calls, Group chats, Promotions. Each has its own toggle and its own importance level. A channel set to Silent posts without sound or a heads-up banner, which looks identical to “notifications are broken”.

Set the channels you care about to Default or High and enable Pop on screen.

Fix 4 - Do Not Disturb and Modes

If notifications arrive but silently, this is where to look.

• Settings → Notifications → Do Not Disturb. Check whether a schedule is active that you forgot about.
• Modes (Android 15+) and Samsung Modes and Routines can apply their own notification filters per mode — Sleep, Driving, Work. A routine triggered by location or time can silence apps without any visible indicator.
• Bedtime mode under Digital Wellbeing silences everything on a schedule.
• Check that Priority only exceptions include the apps you need.

Also worth checking: a paired smartwatch. Wear OS and Galaxy Watch both suppress phone notifications while the watch is connected and worn, forwarding them to the watch instead. If the watch is on the charger in another room, they go nowhere.

What not to do

• Do not install a “notification fixer” app. None of them can grant themselves the permissions needed to exempt other apps from battery restrictions. They add background load, which makes the problem worse.
• Do not clear storage on the app. It will not fix a battery restriction and it logs you out while deleting local data — see clear cache vs clear storage.
• Do not turn on battery saver and expect notifications to work. Battery saver restricts background activity by design. The two goals are in direct conflict.
• Do not use an aggressive task killer or “RAM booster”. Killing processes is exactly what breaks push delivery.

Check in this order

1. Set the app’s battery usage to Unrestricted.
2. Turn off Put unused apps to sleep and clear the sleeping-apps lists (Samsung), or enable Autostart (Xiaomi, OnePlus, Oppo).
3. Confirm the notification permission is granted and the relevant channels are set to Default or High.
4. Check Do Not Disturb, Modes, Bedtime mode and any routine schedule.
5. Disconnect a paired watch and test.
6. Restart the phone — it re-registers every app with Firebase.

If notifications still fail after all of this for one specific app, the problem is likely in the app’s own settings rather than Android’s. Many apps have an internal notification configuration that is separate from the system one.

Finally, if you turned several apps to Unrestricted and battery life dropped noticeably, that is worth measuring rather than guessing at — see which app is draining your battery for how to read the stats properly.