This is the code that gets info from the database:

    ManagerAdminApi(String strApiUrl) {
        ApiUrl = strApiUrl;
        String BASE_URL = ApiUrl + "admin/";
        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
        logging.setLevel(HttpLoggingInterceptor.Level.BODY);
        OkHttpClient.Builder httpClient = new OkHttpClient.Builder();
        httpClient.addInterceptor(logging);
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(BASE_URL)
                .addConverterFactory(GsonConverterFactory.create(new GsonBuilder().setLenient().create()))
                .client(httpClient.build())
                .build();
        service = retrofit.create(InterfaceAdminApi.class);
    }

The expected behaviour is that I get information like this:
[
    {
        "id": 1,
        "username": "admin",
        "password": "$2y$10$1h8jP8./G2bvlai3Prgwuu9fHHFsunerV0/aFo.JKKcWPh1MelyHy",
        "created": "2018-04-15T11:53:28-05:00",
        "midified": "2018-04-15T11:53:28-05:00",
        "grade": 4,
        "department": 5
    }
]

It is currently returning a null value for each item