Do you have trouble getting Outlook calendars to sync with your Apple iPhone? It can be frustrating—not to mention unnerving—when important events and appointments fail to appear within Microsoft Outlook or the native Calendar app.

In this troubleshooting guide, you’ll learn various methods to fix Outlook calendar synchronization issues on the iPhone. You can also use them to troubleshoot similar problems on the iPad and iPod touch.

Table of Contents
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    1. Enable the Calendar (Outlook App Only)

    If the events for a specific calendar fail to sync in Outlook for iOS, it could be because the calendar’s not enabled within the app. To check and fix that:

    1. Switch to the Calendar tab in Outlook.
    2. Tap your profile portrait or initials on the top-left corner of the screen.
    3. Check the list of calendars. If the calendar is inactive, tap to enable it.
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    2. Activate Calendar Syncing (iOS Calendar Only)

    If none of your Outlook calendars appear within the iPhone’s native Calendar, the chances are your Outlook account is not set to sync with the app. If you only see your iCloud calendars:

    1. Open the Settings app.
    2. Scroll down and tap Calendar.
    3. Tap Accounts.
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    1. Tap Outlook.
    2. Turn on the switch next to Calendars if it’s inactive.
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    3. Force-Quit and Relaunch Outlook/Calendar

    Occasionally, the Outlook app or iOS Calendar can malfunction and stop syncing the latest Outlook calendar events. To fix that:

    1. Swipe up from the bottom of the screen to bring up the App Switcher. If you use an iPhone with Touch ID, double-click the Home button.
    2. Drag the Outlook or Calendar card to the top of the screen to remove it.
    3. Exit to the Home Screen and relaunch Outlook or the default Calendar app.
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    4. Check the Outlook Server Status

    Next, check the Outlook system status to rule out server-side issues from the equation. To do that, head to the Office Service Status portal and check the Current status next to Outlook.com. If there’s a problem, wait until Microsoft fixes it.

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    5. Toggle Airplane Mode on iPhone

    Unexpected internet issues are another reason that prevents your Outlook calendars from syncing. If you’re looking for a quick way to restore connectivity, try enabling and disabling your iPhone’s Airplane Mode.

    To do that, swipe down from the screen’s top-right to open the Control Center. Then, tap the Airplane Mode icon, wait for 10 seconds, and tap it again.

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    If the problem persists, switch from Wi-Fi to cellular data or vice versa. Or, connect to another Wi-Fi hotspot and check if that makes a difference.

    6. Restart Your iPhone

    A system software reboot refreshes the iPhone’s memory and clears potential glitches or errors preventing Outlook calendars from syncing. Additionally, the procedure resets your network connections and reestablishes communication between the device and the Outlook servers.

    To do that, invoke Siri (press and hold the Side/Home button), say Restart iPhone, and tap Restart on the confirmation pop-up.

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    7. Enable Background App Refresh (Outlook App Only)

    If Background App Refresh for Outlook is inactive on an iPhone, calendar data syncing fails unless the app runs in the foreground. If that’s what you’re dealing with:

    1. Open the Settings app.
    2. Scroll down and tap Outlook.
    3. Enable Background App Refresh to provide the app permissions to run in the background.
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    8. Disable Low Data Mode on iPhone

    iOS devices come with Low Data Mode, which restricts background data usage on Wi-Fi and cellular. Disabling the feature could fix iPhone calendar sync issues.

    Disable Low Data Mode on Wi-Fi

    1. Open the Settings app and tap Wi-Fi.
    2. Tap the Info icon next to the active Wi-Fi connection.
    3. Disable the switch next to Low Data Mode.
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    Disable Low Data Mode on Cellular

    1. Open Settings and tap Cellular.
    2. Tap Cellular Data Options.
    3. Disable Low Data Mode.
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    9. Disable Low Power Mode on iPhone

    Low Power Mode minimizes background activity to conserve battery life on the iPhone. If the amount of remaining battery isn’t an immediate concern, try deactivating the feature:

    1. Open the Settings app.
    2. Tap Battery.
    3. Disable the switch next to Low Power Mode.
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    10. Reset Account (Outlook App Only)

    The Outlook app for iOS lets you reset problematic accounts with synchronization problems. It’s a relatively straightforward process and you won’t lose any data. To reset an account in Outlook:

    1. Open the Outlook app and tap your profile portrait or initials on the top left corner.
    2. Select Settings.
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    1. Tap your Outlook email account under Mail Accounts.
    2. Tap Reset Account.
    3. Tap OK. Outlook should automatically shut down.
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    1. Relaunch the Outlook app to finalize the Outlook account reset.

    11. Delete and Re-Add Account (iOS Calendar Only)

    If the iOS Calendar fails to sync calendars from Outlook, try deleting and re-adding the Outlook account on your iPhone. That should refresh the account’s settings and fix underlying configuration errors. To do that:

    1. Open the Settings app.
    2. Go to Calendar > Accounts.
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    1. Select Outlook.
    2. Tap Delete Account.
    3. Tap Delete from My iPhone.
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    1. Restart your iPhone.
    2. Return to Settings > Calendar > Account, tap Add Account, and re-add the Outlook account. Once you do that, don’t forget to sync iPhone Calendar with Outlook.

    12. Update iOS and the Outlook App

    Newer version updates for the iPhone’s operating system (iOS) or the Outlook app could contain bug fixes that address persistent calendar sync issues. Check for and install them next.

    Update the iPhone’s System Software

    Note: Updating the iPhone’s operating system also updates the Calendar app to its latest version.

    1. Open the Settings app.
    2. Go to General > Software Update.
    3. Tap Download and Install.
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    Update the iPhone Outlook App

    1. Open the App Store.
    2. Search for the Outlook app.
    3. Tap Update.
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    13. Reset Network Settings on iPhone

    Resetting the iPhone’s network settings resolves possible Wi-Fi connectivity issues or other network configuration problems stopping Outlook calendars from syncing. To do that:

    1. Open the Settings app on your iPhone.
    2. Tap General > Transfer or Reset iPhone.
    3. Tap Reset.
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    1. Tap Reset Network Settings.
    2. Enter your device passcode and tap Reset Network Settings again to confirm.
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    Note: You must manually rejoin Wi-Fi networks after the network reset procedure.

    Don’t Miss Your Outlook Calendar Events

    Syncing Outlook calendars with an iPhone shouldn’t be a hassle. With the solutions above, you should be able to troubleshoot and resolve sync problems quickly and easily. From checking your calendar settings and disabling conflicting options to updating the system software, there are multiple ways to fix Outlook calendars and keep them up-to-date on your iOS devices.

    That said, complications on non-Apple devices could also stop Outlook calendars from syncing. Learn how to fix Outlook sync problems on Windows, macOS, and Android.