I'm trying to access the SharePoint REST service and trying to upload objects using the curl command. I have followed the steps from this blog.

I was able to get pass through steps until getting the access token. After that when I tried to access the REST point https://<domain_name>.sharepoint.com/Internal_Documents/_api/web/. I'm getting access denied error with HTTP status code 403 Forbidden.

Response 
{
    "odata.error": {
        "code": "-2147024891, System.UnauthorizedAccessException",
        "message": {
            "lang": "en-US",
            "value": "Access denied. You do not have permission to perform this action or access this resource."
        }
    }
}