Microsoft Calendar REST API - Access to OData is disabled

I'm trying to access Microsoft's Outlook.com Calendar REST API. I got OAUTH2 authentication set up correctly and have a valid access token and refresh token available.

However, if I try to access the calendar list @ https://outlook.office.com with my access token:

GET /api/v1.0/me/calendars HTTP/1.1
Accept: application/json; odata.metadata=none
Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciO[...]

the service returns with an 403 Forbidden

HTTP/1.1 403 Forbidden
Cache-Control: private
Transfer-Encoding: chunked
Content-Type: application/json;odata.metadata=minimal;odata.streaming=true;IEEE754Compatible=false;charset=utf-8
Server: Microsoft-IIS/8.5
Set-Cookie: ClientId=OD6KHQBTKOKMLXUI8OJEG; expires=Wed, 21-Sep-2016 18:37:21 GMT; path=/; secure; HttpOnly
Set-Cookie: exchangecookie=8e4f582170cb445780c7148e9494b293; expires=Thu, 22-Sep-2016 18:37:23 GMT; path=/; HttpOnly
Set-Cookie: ClientId=OD6KHQBTKOKMLXUI8OJEG; expires=Wed, 21-Sep-2016 18:37:21 GMT; path=/; secure; HttpOnly
request-id: 7113f37d-69e0-4f8c-a264-9f3599d47899
X-CalculatedBETarget: CY1PR08MB1801.namprd08.prod.outlook.com
X-BackEndHttpStatus: 403
OData-Version: 4.0
X-AspNet-Version: 4.0.30319
X-DiagInfo: CY1PR08MB1801
X-BEServer: CY1PR08MB1801
X-Powered-By: ASP.NET
X-FEServer: AM3PR04CA0074
X-MSEdge-Ref: Ref A: D69A31E4FAA44258B0B8C351A71D2F9E Ref B: 0D3CA60C0976F50C452293F8CF403D8C Ref C: Tue Sep 22 11:37:23 2015 PST
Date: Tue, 22 Sep 2015 18:37:22 GMT

{"error":{"code":"ErrorAccessDenied","message":"Access to OData is disabled."}}

I played around with Outlook's OAuth Sandbox, where the same request returns a 200 OK with the correct data in the body. Strangely enough, they spot a nice little Show me the cURL! button in the sandbox, but this exact curl command will fail again with a 403 error in my terminal.

What am I missing?

Solution

I talked to a Microsoft techie. My problem was, that the REST API is not public (yet) and Microsoft has not yet enabled the API for standard Outlook.com accounts.

I requested an Outlook developer preview account with the REST API enabled by writing an email to [email protected]

It took some time until I got a response from Microsoft, but using the developer account everything works now as expected.