Notifications delayed or not coming

Late notifications are almost always caused by a battery-saving feature putting the app to sleep, or a silent mode left on.

What you seeMessages appear only when you open the app; no sound or banner

1. Silent modes

• Do Not Disturb / Focus. Android: swipe down and look for Do Not Disturb or a Modes tile; Settings › Notifications › Do Not Disturb, and check its schedules. iPhone: open Control Centre and look at the Focus button; Settings › Focus lists Do Not Disturb, Sleep, Work and their schedules. A moon or other focus icon on the lock screen means one is on.
• The ringer. iPhone: the side switch or Action button set to silent. Android: volume key, then check the notification volume slider, which is separate from media volume.
• Flight mode off.

2. The app's notification switches

• Android: Settings › Apps › the app › Notifications: the master switch on, and each category (Messages, Groups, Calls) on with sound, not "Silent". From Android 13, a newly installed app must ask for permission to notify; if you tapped "Don't allow", turn it on here.
• iPhone: Settings › Notifications › the app › Allow Notifications on, with Lock Screen, Notification Centre and Banners ticked and Sounds on. If "Time Sensitive" is offered, turn it on for message apps.
• Inside the app: WhatsApp › Settings › Notifications; also check that the chat or group itself is not muted (a crossed speaker icon beside it).

3. Battery restrictions (the main cause on Android)

To save power, Android and many phone makers stop apps that run in the background. A messaging app that has been stopped cannot receive anything until opened.

1. Settings › Apps › the app › App battery usage (or Battery) › choose Unrestricted.
2. Turn off Battery Saver to test: Settings › Battery.
3. On the same app screen, turn off Pause app activity if unused (Remove permissions and free up space).
4. Maker-specific switches. Xiaomi, Redmi and Poco: Settings › Apps › Manage apps › the app › Autostart on, and Battery saver › No restrictions. Vivo, Oppo, Realme and OnePlus: Settings › Battery › look for "Background power consumption management", "App battery management" or "Allow background activity" and allow the app; also allow Auto-launch. Samsung: Settings › Battery › Background usage limits › add the app to Never auto sleeping apps.
5. Lock the app in recents. On several brands, open the recent-apps screen, press and hold the app's card and choose Lock, so that "clear all" does not close it.

Names vary by brand and version; search Settings for "battery" and "autostart".

4. Data restrictions

• Android: Settings › Apps › the app › Mobile data & Wi-Fi › Background data on, and "Unrestricted data usage" on if you use Data Saver. Settings › Network & internet › Data Saver off to test.
• iPhone: Settings › Mobile Service: the app's switch on. Settings › General › Background App Refresh on for the app. Low Data Mode (Settings › Mobile Service › Mobile Data Options, and in each Wi-Fi network's settings) delays background activity; turn it off.
• Low Power Mode on iPhone delays mail fetching and background refresh.

5. Connection

Notifications travel over a constant link to Google's or Apple's servers. A weak signal, or a Wi-Fi network that drops idle connections, delays them.

• Test on mobile data with Wi-Fi off, and the reverse. If alerts are late only on one Wi-Fi, restart that router.
• Turn off VPNs and ad-blocking "private DNS" settings to test.
• See mobile data not working and Wi-Fi not connecting.

6. Refresh the app and the system

1. Restart the phone.
2. Update the app and the system.
3. Android: clear the app's cache. See clear cache and app data.
4. Sign out of the app and in again, or reinstall it (back up chats first).
5. Android: update Google Play services from the Play Store.

7. Email in particular

• Gmail: Settings › your account › Notifications: All; and "Sync Gmail" ticked. Android Settings › Passwords & accounts › "Automatically sync app data" on.
• iPhone Mail: Settings › Apps › Mail › Mail Accounts › Fetch New Data › Push on, or Fetch every 15 minutes.

8. Notifications arrive but make no sound

Check the notification volume, that the app's category is not set to "Silent" (Android) or Sounds off (iPhone), that a Bluetooth device is not taking the sound, and that the chat is not muted.

For Android phones and iPhones. Written in November 2026 for Android 13 to 15 and iOS 17 and 18. Phone makers rename menus; use the search box in Settings if a name differs. Back up before any reset. This is an independent guide, not connected with Google, Apple, Samsung or any phone maker or operator.