Spotify Artist can't be found

Hej,

if I do a spotify search for "spotify:artist:53sIBaVjXQhfH89Vu6nEGh" I can clearly find an artist page, if I know try:

curl "http://developer.echonest.com/api/v4/artist/terms?api_key=$KEY&format=json&id=spotify-WW:artist:53sIBaVjXQhfH89Vu6nEGh" | python -mjson.tool

I just get

{
    "response": {
        "status": {
            "code": 5,
            "message": "The Identifier specified does not exist",
            "version": "4.2"
        }
    }
}

as a response. Is the mapping between spotify artists and EchoNest not complete?

Is there a nice way to upload hundreds of artists to a catalog without this problem? If just one artists can't be mapped my whole requests is invalid and I don't really want to make a post request for every single artist.