I'm using the Microsoft Graph Explorer on the Microsoft Planner (formerly Tasks) API.

I can requests users fine, e.g. /beta/users.

But when I try to access my plans using /beta/me/plans or /beta/plans/{ID}, I get an unknown error with the details below:

Status Code: 403

{
    "error": {
        "code": "UnknownError",
        "message": "",
        "innerError": {
            "request-id": "62299f57-1792-4b0c-8b60-8613c54f4f50",
            "date": "2017-01-17T21:12:51"
        }
    }
}

I'm trying to query the tasks on a plan that I own.

This API has changed. This URL should be

GET https://graph.microsoft.com/v1.0/me/planner/plans