Go to Settings → Notifications → the affected app and turn on Allow Notifications plus the alert locations you want. Then check Focus modes and whether an Apple Watch is receiving the alert instead.
Start with the simplest reversible checks before moving to resets or repair.
Why this happens
Do not assume the most expensive failure first. This problem usually becomes much easier once you separate a settings problem from a connection, app, accessory or hardware problem.
- Notifications may be disabled for that app.
- Lock Screen, Notification Center or Banner alerts may be off even when notifications are allowed.
- Focus modes can silence or filter selected apps/people.
- A Messages conversation can have Hide Alerts enabled.
- With Apple Watch, notifications normally appear on either the watch or iPhone rather than both.
Fix it in this order
- Open Settings → Notifications → affected app and turn on Allow Notifications.
- Choose the alert locations you want: Lock Screen, Notification Center and/or Banners.
- Check Focus settings and any automatic schedules.
- For Messages, open the affected conversation and make sure Hide Alerts is off.
- If you wear an Apple Watch, check whether the notification is being routed there.
- Restart the iPhone and update iOS and the affected app.
- Send a controlled test notification while the iPhone is locked.
How to identify the real cause
If one app is missing alerts, focus on that app's settings. If many apps are silent, inspect Focus, mute state and paired-device behavior. If alerts appear visually but make no sound, this is a sound/silence problem rather than missing delivery.
Common mistakes that waste time
- Turning on Allow Notifications but leaving every alert location off.
- Forgetting a scheduled Focus mode.
- Expecting the same alert on both Apple Watch and iPhone by default.
- Treating a muted Messages conversation as a system-wide notification failure.
Why the troubleshooting order matters
Good troubleshooting changes one variable at a time. Start with the checks that are fast, reversible and low risk. If the problem disappears after one change, stop there and verify it for a while instead of continuing to reset unrelated settings.
Also pay attention to scope. A problem affecting one app or one accessory usually deserves app/accessory troubleshooting. A problem affecting everything on the device points more toward a system setting, network, driver or hardware issue.
When this is probably not a settings problem
If a specific app still fails after its notification settings are correct, check the app's internal notification/account settings and developer support.
If you need repair or manufacturer support, write down what you already tested. A short list of known-good cables, devices, networks or apps you tried is much more useful than saying only that the feature “doesn't work.”
Separate missing alerts from silent alerts
Open Notification Center after a test message. If the notification is present but you did not hear or see a banner, delivery worked — alert presentation is the issue. If it is absent entirely, investigate app settings, Focus filters, account sync and the app itself.
Apple Watch changes expectations
When an Apple Watch is paired, notification routing depends on which device is active. This can make an iPhone look as if it missed an alert even though the watch received it exactly as designed.
Once one step appears to work, stop and reproduce the original problem under the same conditions. If it stays fixed, leave unrelated settings alone. That preserves a clear cause-and-effect trail and avoids creating a second problem while trying to solve the first.
If the symptom returns, write down the trigger, time, network, battery level, connected accessories and app in use. Those details make the next diagnostic step much more precise and are useful if you eventually need manufacturer or developer support.
Frequently asked questions
Why do notifications go to my Apple Watch but not iPhone?
Apple says notifications generally go to either the Apple Watch or iPhone, depending on device state and settings.
Why do notifications appear but make no sound?
The iPhone may be silenced, alert sounds may be disabled or a Focus mode may be active.
Can one Messages chat be muted?
Yes. Hide Alerts can mute a specific conversation.
Where do I enable banners?
Settings → Notifications → app, then choose Banners under Alerts.
Official sources used
Techresque uses manufacturer documentation as the primary factual source for these troubleshooting guides. Menu names can vary by model, Android skin, iOS version or Windows build.