POST请求期间在Retrofit中出现服务器错误500

Question

我在Slim 3中设计了rest api，它将客户详细信息存储在MySQL db中。我正在使用Retrofit 1.9连接到webservice。我收到服务器错误500，其中同样的请求在POSTMAN中正常工作。

var mapper = Mappers.Xy<MeasureModel>()
           .X(model => model.DateTime.Ticks)   //use DateTime.Ticks as X
           .Y(model => model.Value);           //use the value property as Y

//The next code simulates data changes every 500 ms
Timer = new Timer
{
    Interval = 1000
};
Timer.Tick += TimerOnTick;
R = new Random();
Timer.Start();

ChartValues.Add(new MeasureModel
{
    DateTime = now,
    Value = R.Next(0, 5)
});

接口：

   //using retrofit
        RestAdapter adapter = new RestAdapter.Builder().setEndpoint(Config.CUSTOMER_URL).build();
        RegisterCustomer api = adapter.create(RegisterCustomer.class);
        api.registerCustomer(custName.toString(),
                             phoneNumber.toString(),
                             address.toString(),
                             Config.API_KEY, new Callback<retrofit.client.Response>() {
                    @Override
                    public void success(retrofit.client.Response result, retrofit.client.Response response) {
                        BufferedReader reader = null;
                        String output = "";
                        try {
                            reader = new BufferedReader(new InputStreamReader(result.getBody().in()));
                            output = reader.readLine();

                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        Log.d("customer result",result.getBody()+"##"+result.getStatus() +"##" +response.getBody().toString());
                    }

                    @Override
                    public void failure(RetrofitError error) {
                        Log.d("customer save fail ",error.getMessage());
                    }
                });

我的PHP代码。

 public interface RegisterCustomer
{
    @FormUrlEncoded
    @POST("/customer")
    public void registerCustomer(
            @Field("cust_name") String cust_name,
            @Field("phone") String phone,
            @Field("address") String address,
            @Field("apikey") String apikey,
            Callback<Response> callback);
}