Troubleshoot Outlook Calendar integration issues in Todoist

Available for

  • Beginner
  • Pro
  • Business

Platforms

  • macOS
  • iOS
  • Android
  • Windows 10

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:

  1. Log in to Todoist at https://todoist.com.
  2. Click your avatar at the top-left.
  3. Select Settings.
  4. Click the Calendar tab.
  5. 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.

Log in to the correct Outlook account

If you have two or more Outlook accounts, and you initially logged in with one of these, Todoist may consistently and automatically log in to that account without giving you the option to choose another account. To fix this:

  1. Log in to Todoist at https://todoist.com.
  2. Click your avatar at the top-left.
  3. Select Settings.
  4. Click the Calendar tab.
  5. Disconnect the Outlook integration.
  6. Revoke calendar access to the Microsoft account for Todoist:
    • Microsoft personal account: Open this link and click Don’t allow for the Todoist Outlook Calendar app.
    • Microsoft 365 business account: Open this link and click the three dots icon on the Todoist Outlook Calendar app. Then, click Remove.
  7. Log in to the correct Microsoft account.
  8. Reconnect the calendar integration.

About 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.

Errors

Here are some of the known errors with the Outlook Calendar integration, and steps to resolve them:

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:

  1. Disconnect the Outlook integration.
  2. Log out and log back in to Todoist.
  3. Reconnect the calendar integration.

You'll see a 403 Forbidden error 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.

You'll see a 404 Not Found error if Todoist can't 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, read the official Microsoft permissions overview documentation or the Todoist Security and Privacy FAQ.

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.