azure active directory - To-Do API: The Service is not available

Question

When calling the MS Graph API on the endpoint https://graph.microsoft.com/beta/me/todo/lists, I get the following result (same when using v1.0 instead of beta):

{
    "error": {
        "code": "UnknownError",
        "message": "The service is unavailable.",
        "innerError": {
            "date": "2021-01-05T18:36:43",
            "request-id": "a4549f79-399a-401b-84eb-cc2f8f6197c8",
            "client-request-id": "e07b23bb-60bd-be9b-39db-60953ff42844"
        }
    }
}

Permission Tasks.ReadWrite is consented and the authenticated user account is a personal account (aka Microsoft Account). With a "Work or school account", the API works as expected.

As of the documentation, this endpoint should be fully available in v1.0 and beta versions but it obviously is not - or I do something wrong. Any suggestions?

Answer 1

You can try to use graph-explorer to log in to your personal Microsoft account and call the api. I just tested it with this tool and it did work for me. (Don't forget to add Tasks.ReadWrite permission and consent)

Another method is to add your personal Microsoft account as a guest user to the Azure tenant (note: guest users need administrator role to call the api), then grant Tasks.ReadWrite delegation permissions to the application, and then use the auth code flow Obtain an access token. This requires you to log in to your personal Microsoft account to obtain an authorization code, and then use the authorization code to redeem an access token.