Zebra ZT410

I am developing a web-application (.net, c#) that needs to print png files using Zebra ZT410 printer. I am trying to use code from zebra examples (connect to printer with TCP/IP, port 9100 and print a sample text) - Zebra Technologies - Send ZPL Commands via TCP/IP in C#

I don't get any errors, but nothing is printing. I tried port 6101 too, no luck.

Any suggestions why it is not working?

 

            string ZPLString =

             "^XA" +

             "^FO50,50" +

             "^A0N50,50" +

             "^FDHello, World!^FS" +

             "^XZ";

 

 

            try

            {

                // Open connection

                System.Net.Sockets.TcpClient client = new System.Net.Sockets.TcpClient();

                client.Connect(ipAddress, port);

 

 

                // Write ZPL String to connection

                System.IO.StreamWriter writer =

                new System.IO.StreamWriter(client.GetStream());

                writer.Write(ZPLString);

                writer.Flush();

 

 

                // Close Connection

                writer.Close();

                client.Close();

            }

            catch (Exception ex)

            {

                Console.WriteLine(ex);

            }

            Console.Read();