Error when I print a Barcode in IMZ320 with C# Xamarin Forms

I'm using LINK-OS Plugin via Bluetooth with the next code (in IMZ320):

public async Task printBarCode(string code)

        {

            if ((connection != null) && (connection.IsConnected))

            {

                //This is an example of a Code 39 bar code: ^B3

                string zpl = "^XA^FO100,100^BY3^B3N,N,100,Y,N^FD" + code + " ^FS^XZ";

                try

                {

                    connection.Write(Encoding.UTF8.GetBytes(zpl));

                }

                catch (Exception e)

                {

                    await UserDialogs.Instance.AlertAsync("Se dio la siguiente excepción: " + e.Message + ".", "Excepción", "Aceptar");

                }

            }

        }

but when I print this, nothing happens, any suggestion?