There are several types of error messages you might encounter in Microsoft To Do.

This may be due to your network connection. Using a VPN, proxy, or firewall could cause sync issues with To Do. Contact your IT admin to have these URLs approved:

  • .microsoft.com

  • .msecnd.net

  • .live.com

  • graph.windows.net

  • graph.microsoft.com

  • .office.com

  • .office.net

  • .office365.com

  • static2.sharepointonline.com

  • todo-web-endpoint.azureedge.net

  • .microsoftonline.com

  • .microsoft.io

  • .windows.net

  • microsoft-my.sharepoint.com

  • microsoft.sharepoint.com

  • login.microsoftonline.com

Make sure your IT admin also turns on these ports:

  • 443

  • 80

  • 587

If you're trying to sign in to Microsoft To Do on the web and see a 503 error, this could be related to limitations in the local network or restrictions on a corporate network.

Check with your IT admin to make sure none of these URLs are blocked:

  • .microsoft.com

  • .msecnd.net

  • .live.com

  • graph.windows.net

  • graph.microsoft.com

  • .office.com

  • .office.net

  • .office365.com

  • static2.sharepointonline.com

  • todo-web-endpoint.azureedge.net

  • .microsoftonline.com

  • .microsoft.io

  • .windows.net

  • microsoft-my.sharepoint.com

  • microsoft.sharepoint.com

  • login.microsoftonline.com

Please follow the steps mentioned below to fix the error: 

Mac users: 

  1. Uninstall the To Do app

  2. Open Finder

  3. Press CMD+Shift+G and enter ~/Library/Group Containers/UBF8T346G9.com.microsoft.to-do-mac/AccountData/userdatabase.db

  4. Delete this file

  5. Download the To Do app from the App Store again

iOS users:  

Reinstall the To Do app from the App Store 

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