You see a red banner in Notion that says “Calendar Sync Failed” and your events no longer update. This error occurs when Notion loses its connection to your external calendar provider, such as Google Calendar or Outlook. The root cause is typically an expired OAuth token, a revoked permission, or a change in your calendar account password. This article explains why the sync breaks and provides clear steps to reauthorize the connection so your calendar data stays current.
Key Takeaways: Reauthorizing Your Calendar in Notion
- Settings & Members > Connections > Calendar provider: Disconnect the broken calendar integration and reconnect it to refresh the OAuth token.
- Google Calendar or Outlook account settings: Verify that Notion still has permission to read and write to your calendar. Revoked permissions cause the sync failed error.
- Notion desktop or mobile app restart: After reconnecting, close and reopen Notion to force the new authentication token to take effect.
Why the Calendar Sync Fails in Notion
Notion uses OAuth 2.0 tokens to connect to Google Calendar and Microsoft Outlook calendars. These tokens have an expiration time set by the provider. When the token expires and Notion cannot refresh it automatically, the sync fails. Other causes include:
- You changed your Google or Microsoft account password, which invalidates all existing tokens.
- You manually revoked Notion’s access from your calendar provider’s security settings.
- Your calendar provider’s server returned a temporary error, and Notion did not retry the sync.
- You reached the maximum number of connected calendars allowed by your Notion plan or provider.
The sync failure banner appears for each calendar that lost its connection. You must reauthorize each affected calendar individually.
Steps to Reauthorize a Calendar Connection in Notion
Follow these steps to disconnect and reconnect your calendar. The process is the same for Google Calendar and Outlook.
- Open Notion and go to Settings & Members
Click your profile picture or the workspace icon in the top-left corner of the Notion sidebar. From the menu, select Settings & Members. - Navigate to My Connected Apps
In the left sidebar of the Settings page, click My connected apps. This section lists all external services linked to your Notion account. - Find the calendar integration
Look for Google Calendar or Microsoft Outlook Calendar in the list. Click the Manage button next to the calendar that shows the sync failed error. - Disconnect the calendar
On the integration details page, click Disconnect. A confirmation dialog appears. Click Disconnect again to confirm. This removes the old, expired token. - Reconnect the calendar
After disconnecting, click Connect next to the same calendar provider. Notion opens a new browser tab or window requesting permission. Sign in to your Google or Microsoft account if prompted. Grant Notion permission to view and manage your calendar events. - Select the calendars to sync
After authorizing, Notion shows a list of your calendars. Check the boxes next to the calendars you want to sync. Click Save or Connect to finish. - Restart Notion
Close the Notion desktop app or browser tab completely. Reopen Notion. The sync failed banner should disappear within a few seconds. Check your calendar view to confirm events are loading.
If you still see the error after reconnecting, repeat the steps and ensure you grant all requested permissions during the OAuth flow. Some corporate Google Workspace or Microsoft 365 accounts block third-party app permissions. Contact your IT administrator to allow Notion access.
If Notion Still Shows Sync Failed After Reauthorization
Calendar events do not appear after reconnecting
Wait up to five minutes for the initial sync to complete. Notion syncs calendars on a schedule, not instantly. If events still do not appear, manually refresh the page by pressing Ctrl+R or Cmd+R. You can also toggle the calendar view off and on in the database view options.
Notion asks to reauthorize every time you open the app
This indicates the token is not being stored properly. Clear your browser cache or reinstall the Notion desktop app. On Windows, go to Settings > Apps > Notion > Advanced > Reset. On macOS, delete the app and download a fresh copy from notion.so/download.
Multiple calendars show the sync failed error
Disconnect and reconnect the entire calendar provider integration, not individual calendars. In My connected apps, click Manage on the provider and then Disconnect. Reconnect and select all calendars again in one session.
Outlook calendar sync fails after Microsoft 365 password change
Microsoft invalidates all OAuth tokens when you change your password. You must follow the disconnect and reconnect steps above. Additionally, check your Microsoft account’s App permissions page at account.microsoft.com/security and remove any old Notion entries before reconnecting.
Notion Calendar Sync Features: Connected vs Disconnected State
| Item | Sync Connected | Sync Failed |
|---|---|---|
| Event creation in Notion | Events created in Notion appear in Google/Outlook calendar within seconds | New events are saved locally in Notion but never pushed to the external calendar |
| Event updates from provider | Changes made in Google/Outlook calendar appear in Notion automatically | Notion shows outdated event data or no events at all |
| Calendar selection | You can choose which sub-calendars to sync from the provider | All previously selected calendars go offline until reauthorization |
| Authentication token lifetime | Token refreshes automatically every hour for Google, every 90 days for Microsoft | Token expired or revoked; manual reconnection required |
The sync failed error does not delete any events from your Notion database. Once you reconnect, Notion merges the external calendar data with your local database. Duplicate events may appear if you created events in both places while sync was down. Delete duplicates manually by sorting your calendar view by creation date.
You can now reauthorize any calendar that shows the sync failed error using the disconnect and reconnect method in My connected apps. To prevent future issues, check your calendar provider’s app permissions page every few months and confirm Notion still has access. If you manage multiple workspaces, repeat these steps in each workspace separately because calendar connections are per-workspace, not per-account.