Download binary file from my FTP server

Hi Guys! I want to download a binary file from my FTP server and extract the class data. I have written the code but there seems to be an error. Can you please help me with this. Here's the code:

 public class FileDownload : MonoBehaviour 
 {
     XYZ data;
     FileSave Vars;
     public string FTPHost = "ftp://files.myserver.com";
     public string FTPUserName = "username";
     public string FTPPassword = "password";
 
     public void Download()
     {
         BinaryFormatter BF = new BinaryFormatter();
         WebClient client = new System.Net.WebClient();
         Uri uri = new Uri(FTPHost + '/' + "ABC.dat");    
         client.Credentials = new System.Net.NetworkCredential(FTPUserName, FTPPassword);
         byte[] DATA = client.DownloadData(uri);
         Stream stream = new MemoryStream(DATA);
         data = (XYZ)BF.Deserialize(stream);
         Vars.A = data.X;
         Vars.B = data.Y;
     }
 }