Is your Outlook Calendar not syncing correctly with Todoist? Are events missing or changes not reflecting as expected? If you’re running into issues with the Outlook Calendar integration, follow these troubleshooting steps to get everything working smoothly again.
Refresh your calendar manually
Changes made to your Outlook calendars, like adding or removing calendars, won’t automatically update in Todoist. Outlook doesn’t notify us of these changes. To refresh your calendar list:
- Log in to Todoist at https://todoist.com.
- Click your avatar at the top-left.
- Select Settings.
- Click the Calendar tab.
- Under Outlook Calendar, click the Resync button.
This will update your calendar list in Todoist.
Check Microsoft 365 admin consent
For Microsoft 365 Education or Business accounts (office365.com), admin approval might be required to access the Outlook Calendar integration. This happens when Microsoft organizations restrict third-party app consent.
If you see a message indicating that admin approval is needed when trying to connect, request access from your Microsoft 365 admin with the following details:
- Application Name: Todoist for Outlook Calendar
- Application (Client) ID: abdc6ca6-1e22-47a1-aaf9-3265b713b1a8
Your admin can grant organization-wide consent to Todoist by following the steps in Microsoft’s Entra ID documentation.
If your organization has an admin consent workflow, submit a request when connecting Outlook to Todoist. Your admin can then review and approve your request.
After approval, reconnect your Outlook Calendar in Todoist and Resync to ensure everything works properly.
Verify Outlook Calendar permissions
Todoist is a trusted Microsoft partner, and the Outlook Calendar integration follows Microsoft’s recommended OAuth security flow. The integration requests only the necessary permissions:
- Calendars.ReadWrite – Allows Todoist to read and write events in your calendars. This enables you to view calendar events in Todoist and sync scheduled tasks as Outlook events.
- email – Grants access to your email address to confirm which account is connected to Todoist.
These permissions apply to both personal Outlook accounts (live.com) and Microsoft 365 accounts (office365.com).
For more details, see Microsoft’s permissions overview or Todoist’s Security and Privacy FAQ.
Fix the “Out of Sync” error
An “Out of sync” message in your Outlook Calendar settings means Todoist can’t retrieve your calendar data due to an issue on Microsoft’s side.
If your calendars and events appear to be syncing correctly, but the “Out of sync” status remains, try these steps to resolve it:
- Disconnect the Outlook integration.
- Log out of Todoist.
- Log back into Todoist.
- Reconnect the integration.
403 Forbidden error
This happens when Todoist doesn’t have permission to access your calendar because your account is under limited access for third-party apps.
- Example error: ErrorAccessDenied: Access to OData is disabled. Request was blocked due to a Tenant-Configured UserAgent AllowList being set for this user.
- How to fix it: Ask your Microsoft admin to grant the Calendars.ReadWrite and email permissions for Todoist. Some organizations also restrict third-party app access to specific mailboxes through an application access policy.
For more details, check Microsoft’s documentation.
404 Not Found error
This means Todoist is unable to retrieve your Outlook calendar’s data.
- Example error: The mailbox is either inactive, soft-deleted, or is hosted on-premises.
- How to fix it: You may not have an active Microsoft Office 365 license. Contact your Microsoft admin to confirm that a valid license is assigned to your account.
For more details, refer to Microsoft’s community documentation.
Get in touch
If you’ve tried these steps and are still having issues, get in touch with us, sharing details of the issue, including any error messages you see. We— Sergio, Dermot, Marco, or any of our other teammates—will help resolve this for you.
