Notifications that arrive late or not at all on a Galaxy S23 are nearly always caused by Samsung's battery management putting the app to sleep, or by the app's own notification permission, not by a faulty phone. Open the app's notification settings first, then Settings, Battery, Background usage limits and take the app out of Sleeping apps. Android 13 and later asks for notification permission per app, and Do not disturb can silence everything without any obvious sign.
Differential
Likely causes of “Samsung Galaxy S23 notifications are delayed or missing”, and how to tell them apart
- 1
The app is in Sleeping or Deep sleeping apps
What separates it Alerts arrive only when you open the app
How to confirm Settings, Battery, Background usage limits: remove the app from both lists
- 2
Notification permission is off
What separates it No alert, no banner, no badge
How to confirm Settings, Notifications, App notifications: turn the app on and check each channel
- 3
Do not disturb or a Mode
What separates it Silence at set times or while a Mode is active
How to confirm Settings, Notifications, Do not disturb and Modes and Routines: check schedules
- 4
Restricted background data
What separates it Alerts fail on mobile data but work on Wi-Fi
How to confirm Settings, Connections, Data usage: allow background data for the app
- 5
Battery optimization
What separates it Messaging apps deliver in batches
How to confirm Settings, Apps, the app, Battery, choose Unrestricted
- 6
The lock screen hides content
What separates it Alerts arrive but show only Notification, with no text
How to confirm Settings, Notifications, Lock screen notifications, choose to show content
Before you touch a setting
Record this first — changing settings destroys the evidence
- Which app and which kind of alert
- Late or never
- Do not disturb or Mode status
- One UI version
Try in this order
0 of 6 completedCheck the permission
ReversibleSettings, Notifications, App notifications and make sure the app is on, then open the app's own settings for per-channel switches.
Wake the app
ReversibleSettings, Battery, Background usage limits. Under Sleeping apps and Deep sleeping apps remove the app.
Set the app to Unrestricted
ReversibleSettings, Apps, the app, Battery, Unrestricted. Do this for messaging and banking apps only.
Check Do not disturb
ReversibleSettings, Notifications, Do not disturb and any Mode that is on.
Check data restrictions
ReversibleSettings, Connections, Data usage and Data saver: allow the app to use data in the background.
Restart
ReversibleRestart the phone; a stuck notification service clears.
Model-specific
What is true of this model and not of its siblings
- Why Samsung phones delay alerts
- One UI manages background apps aggressively to save battery. On a 3,900 mAh phone it is stricter than on the larger S23 models, and messaging apps are the most common casualties.
- Where the controls are
- Settings, Notifications for the permission and Do not disturb; Settings, Battery, Background usage limits for sleeping apps; the app's own page under Settings, Apps for the Unrestricted option.
Stop boundary
When this stops being a self-service repair
- !If every app misses alerts in Safe mode, book service
- !If a single app is at fault, contact its developer with your One UI version
- !If alerts vanished after an update, check Samsung Members for a known issue
Evidence ledger
Sources behind this answer
Exact questions
Common questions
Why do my messages arrive late on an S23?+
Battery management put the app to sleep. Remove it from Sleeping apps and set it to Unrestricted.
What are Deep sleeping apps?+
Apps that are never allowed to run in the background until you open them, so their alerts never arrive.
Do I need to grant notification permission on Android 13 or later?+
Yes, per app; an app installed after the update asks once and a No answer silences it.
Will Unrestricted drain the battery?+
Slightly, for that app only, so use it sparingly.
Why do I only see an alert when I open the app?+
The app was put in Sleeping or Deep sleeping apps by the battery manager. Remove it from both lists and set it to Unrestricted.
Will smartwatch alerts work if my S23 delays them?+
No. The watch only relays what the phone receives, so fix the phone's alerts first.