I am trying to access the API using the following code:

        HttpResponse<Root> jsonResponse = Unirest.get("http://api.themoviedb.org/3/discover/movie")
         .header("api_key", API)
         .header("adult", "false")
         .header("vote_count.gte", "5")
         .header("release_date.lte", endDate)
         .header("release_date.gte", startDate)
         .header("page", page.ToString())
         .asJson<Root>();
        return jsonResponse.Body;

and I get a 401 response but I don't understand why. I am sure that my api_key is correct.