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:
    • 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.

Common issues

Here are some of the common issues 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 because of specific errors.

  • 403 forbidden error: Todoist doesn’t have permissions to access your calendar’s data because third-party apps have limited access to your account. Admins may also be limiting third-party app access to only a group of mailboxes via an application access policy.

    Contact your admin to ensure that the Todoist app has Calendars.ReadWrite and email permissions granted.

  • 404 not found error: Todoist can't access the calendar's data. You may, for example, see this error: The mailbox is either inactive, soft-deleted, or is hosted on-premise. It means you could be missing a valid Microsoft Office 365 license.

    Contact your admin to check that you have a valid license for your account.

If you see a “Couldn’t connect your account” pop-up message after trying to connect Outlook Calendar to Todoist, check the following:

  • Click Accept on the Microsoft permissions screen that comes after clicking “Connect Outlook Calendar”.
  • Check if you've enabled specific browser security settings. For example, Microsoft Edge has a “Strict” security setting that will block connections to any third-party app.

When integrating both your personal and shared Outlook calendars into Todoist, you might notice duplicate events from these calendars. This is because events from shared calendars are synced alongside your personal events, leading to duplicates when both calendars contain the same event.

If you prefer to hide events from your shared calendars in Todoist:

  1. Click your avatar at the top-left.
  2. Select Settings.
  3. Click the Calendar tab.
  4. Click the visibility icon beside the Outlook Calendar to hide their events.

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.