OnTimer

Google Calendar · Apple Calendar · Outlook Calendar

Calendar Notifications Not Working?
Here's How to Fix Them

If your calendar notifications aren't working, the problem is usually one of a few common issues: notification permissions, Focus Mode, Scheduled Notification Summary, missing event reminders, calendar sync problems, Background App Refresh, or battery restrictions. Work through the checklist below. Most problems can be fixed in just a few minutes.

The most common causes are disabled notifications, Focus Mode or Do Not Disturb, Scheduled Notification Summary, missing event reminders, default alert settings, calendar sync problems, Background App Refresh, and battery restrictions.

What best describes your problem?

Select the closest symptom to jump directly to the most relevant fix.

Notifications never appearJump to fix →Notifications are silentJump to fix →Notifications appear lateJump to fix →Some events notify but others don'tJump to fix →Google Calendar notifications stopped workingJump to fix →Apple Calendar notifications stopped workingJump to fix →Outlook calendar notifications stopped workingJump to fix →Recurring reminders stopped workingJump to fix →

Troubleshooting Guide

Go in order if you are not sure where the problem is. If you already know the symptom, use the symptom links above.

1

Verify notifications are enabled

First, make sure your phone is allowed to show alerts from the calendar app. If this setting is off, event reminders can be configured correctly and still never appear.

Steps

  1. 1.Open Settings on your iPhone.
  2. 2.Tap Notifications.
  3. 3.Choose Calendar, Google Calendar, or Outlook.
  4. 4.Turn on Allow Notifications.
  5. 5.Enable Lock Screen, Notification Center, banners, sounds, and badges while testing.

Platform notes

  • Apple Calendar: check Settings -> Notifications -> Calendar.
  • Google Calendar: check Settings -> Notifications -> Google Calendar, then confirm notifications are enabled inside the Google Calendar app.
  • Outlook: check Settings -> Notifications -> Outlook, then confirm Outlook's in-app notification settings are enabled.
2

Check Focus Mode and Do Not Disturb

Focus modes are one of the most common reasons calendar alerts suddenly stop. A Focus can block notifications silently, especially Work, Sleep, Driving, or Do Not Disturb.

Steps

  1. 1.Open Settings.
  2. 2.Tap Focus.
  3. 3.Turn off the active Focus temporarily.
  4. 4.If notifications start working, reopen that Focus and add your calendar app under Allowed Apps.
  5. 5.Repeat for any Focus mode that turns on automatically by time, location, driving, or app usage.

Platform notes

  • Apple Calendar: allow Calendar through each Focus mode that may be active before events.
  • Google Calendar: allow Google Calendar specifically. Allowing Apple Calendar does not allow Google Calendar.
  • Outlook: allow Outlook specifically, especially for work Focus modes.
3

Check Scheduled Notification Summary

Scheduled Summary can hold notifications and deliver them later in a batch. That is useful for low-priority alerts, but it can make calendar reminders appear late.

Steps

  1. 1.Open Settings.
  2. 2.Tap Notifications.
  3. 3.Tap Scheduled Summary.
  4. 4.Remove Calendar, Google Calendar, and Outlook from the summary list.
  5. 5.Create a test event a few minutes from now to confirm the alert arrives immediately.

Platform notes

  • Apple Calendar: remove Calendar from Scheduled Summary.
  • Google Calendar: remove Google Calendar from Scheduled Summary.
  • Outlook: remove Outlook from Scheduled Summary if work reminders arrive late.
4

Verify the event actually has a reminder

Not every calendar event has an alert attached. Imported events, shared calendars, subscribed calendars, and invitations from other people may use different reminder defaults.

Steps

  1. 1.Open an event that failed to notify you.
  2. 2.Tap Edit or the edit icon.
  3. 3.Look for Alert, Reminder, or Notification.
  4. 4.If it says None, add a reminder such as 10 minutes before.
  5. 5.Save the event, then test another upcoming event from the same calendar.

Platform notes

  • Apple Calendar: open the event -> Edit -> Alert.
  • Google Calendar: open the event -> edit pencil -> notifications.
  • Outlook: open the event -> edit -> Reminder.
5

Check default alert times

If new events are being created without reminders, your default alert settings may be missing or set differently than you expect.

Steps

  1. 1.Check your calendar app's default reminder settings.
  2. 2.Create a new event and confirm whether an alert is added automatically.
  3. 3.If no alert is added, set a default alert time for events.
  4. 4.Review all-day events separately, since many apps use different defaults for all-day reminders.

Platform notes

  • Apple Calendar: Settings -> Calendar -> Default Alert Times. Check Events, All-Day Events, and Birthdays.
  • Google Calendar: open Google Calendar settings, choose the calendar, then check Event notifications and All-day event notifications.
  • Outlook: check Outlook calendar settings for default reminders. Work accounts may enforce their own defaults.
6

Verify calendar synchronization

A reminder can only fire if the event has synced to the device or app that is supposed to notify you. Sync issues often look like notification issues.

Steps

  1. 1.Open the calendar list in your app.
  2. 2.Make sure the calendar that contains the event is visible and enabled.
  3. 3.Confirm the event appears on the same device where you expect the notification.
  4. 4.If you use multiple accounts, confirm the event is not saved to a hidden or inactive calendar.
  5. 5.Check whether the event appears correctly on the calendar provider's web app.

Platform notes

  • Apple Calendar: open Calendar -> Calendars and make sure the relevant iCloud, Google, Exchange, or Outlook calendar is checked.
  • Google Calendar: open the side menu, check the calendar, then open Settings and confirm Sync is enabled for that calendar.
  • Outlook: confirm the Microsoft or Exchange account is connected and the calendar is enabled in Outlook's calendar list.
7

Verify Background App Refresh

Third-party calendar apps need background access to stay current. If background refresh is disabled, notifications may be delayed or fail after calendar changes.

Steps

  1. 1.Open Settings.
  2. 2.Tap General.
  3. 3.Tap Background App Refresh.
  4. 4.Make sure Background App Refresh is on.
  5. 5.Enable it for Google Calendar or Outlook Calendar.

Platform notes

  • Apple Calendar: Apple Calendar is built into iOS, but connected accounts still need to sync correctly.
  • Google Calendar: enable Background App Refresh for Google Calendar.
  • Outlook: enable Background App Refresh for Outlook, especially if work calendar changes do not alert.
8

Disable Low Power Mode while testing

Low Power Mode reduces background activity. It may not be the root cause, but it can make notification and sync problems harder to diagnose.

Steps

  1. 1.Open Settings.
  2. 2.Tap Battery.
  3. 3.Turn off Low Power Mode.
  4. 4.Create a test event three to five minutes from now.
  5. 5.Check whether the notification arrives on time with Low Power Mode off.

Platform notes

  • If notifications only work with Low Power Mode off, keep it disabled before important events while you continue troubleshooting.
  • This is most relevant for Google Calendar and Outlook Calendar because they depend more on app refresh behavior.
9

Force a calendar sync

If the account is connected but events or reminders are stale, force the calendar to refresh before removing accounts or changing deeper settings.

Steps

  1. 1.Open your calendar app.
  2. 2.Refresh the calendar list or main calendar view.
  3. 3.Close and reopen the calendar app.
  4. 4.Create a new test event from another device or web browser.
  5. 5.Confirm the event and its reminder appear on your phone.

Platform notes

  • Apple Calendar: open Calendar -> Calendars, then pull down to refresh.
  • Google Calendar: open Google Calendar, pull down to refresh, then check the calendar's Sync setting.
  • Outlook: pull down on the calendar view to refresh and confirm the account remains connected.
10

Remove and reconnect the calendar account if necessary

Use this as the last reset step. If a calendar account connection is stale or corrupted, reconnecting it can restore event sync and reminder behavior.

Steps

  1. 1.Confirm your calendar data is safely stored in iCloud, Google Calendar, Outlook, Microsoft 365, or Exchange before removing the account.
  2. 2.Remove the affected account from the device or calendar app.
  3. 3.Restart the phone.
  4. 4.Add the account again.
  5. 5.Create a test event with a reminder and confirm it notifies correctly.

Platform notes

  • Apple Calendar: Settings -> Calendar -> Accounts, then remove and re-add the affected account.
  • Google Calendar: sign out and back into the Google account, or remove and re-add the account under iOS Calendar Accounts if Apple Calendar displays your Google events.
  • Outlook: remove and re-add the Microsoft account in Outlook, or reconnect the Exchange or Microsoft account in iOS settings.

If Calendar Notifications Still Aren't Working

If you have checked notification permissions, Focus Mode, Scheduled Summary, event reminders, default alert times, sync, Background App Refresh, Low Power Mode, and account reconnection, the issue may be outside the normal settings path.

At that point, the cause may be one of these deeper problems:

  • An iOS notification bug after an update
  • Google Calendar sync delays
  • Exchange synchronization issues
  • A corrupted local calendar database

For those cases, check the official help documentation for Apple Calendar, Google Calendar, or Microsoft Outlook, especially if the issue started immediately after an operating system update, account change, or calendar migration.

After troubleshooting

Everything working again?

Great.

Native calendar notifications are designed to appear once and then disappear. If you see them at the right moment, that can be enough.

But if you're driving, in another app, away from your phone, in a meeting, or simply distracted, it's still easy to miss them even when everything is configured correctly.

OnTimer doesn't replace your calendar. It connects to your Apple, Google, or Microsoft calendar and turns upcoming events into persistent alarm-style reminders that continue alerting you until you acknowledge them.

The goal isn't to fix broken notifications. It's to make sure you never miss an important event once they're working correctly.

Download on the App Store

iPhone · Apple Calendar · Google Calendar · Outlook Calendar

Calendar Notification Troubleshooting FAQ

Why did my calendar notifications stop working?▾

The most common causes are notification permissions, Focus Mode, Scheduled Notification Summary, missing event reminders, sync problems, Background App Refresh, or Low Power Mode. Start by checking system notification permissions, then check the event itself.

Why are my iPhone calendar alerts silent?▾

Silent iPhone calendar alerts are usually caused by Focus Mode, Do Not Disturb, notification sound settings, Scheduled Summary, or low notification volume. Check Settings -> Focus and Settings -> Notifications -> Calendar first.

Why are Google Calendar notifications delayed?▾

Google Calendar notifications can be delayed when Scheduled Summary is enabled, Background App Refresh is off, Low Power Mode is active, or the calendar has not synced recently. Remove Google Calendar from Scheduled Summary and confirm Sync is enabled for the affected calendar.

Why do recurring reminders stop working?▾

Recurring reminders can stop after a series is edited, imported, moved between calendars, or affected by a sync issue. Open the recurring series, confirm the reminder still exists, then force a calendar sync.

Why are calendar reminders inconsistent?▾

Inconsistent reminders usually mean different events are coming from different calendars, accounts, or default alert rules. Check the calendar source and reminder setting on a few events that worked and a few that failed.

Why do only some events notify?▾

Only some events notify when some events have reminders and others do not, or when events are spread across calendars with different sync and default reminder settings. Shared and subscribed calendars often behave differently from your primary calendar.

Related Guides

Keep your calendar. Add alarms that stay.

OnTimer turns existing calendar events into persistent alarms so important moments are harder to miss.

Download on the App Store

iPhone · Apple Calendar · Google Calendar · Outlook Calendar