Trying to get the zip files via SFTP using SSIS script task (C#)

Question

I am trying to connect to winscp and using below code as a reference to get the zip files from SFTP server. I have added reference for the WinSCPnet.dll assembly. I want to download the ABC_EMP.txt.zip which is placed at Winscp folder location my_data.

Sample-code:

using System;
using Microsoft.SqlServer.Dts.Runtime;
using Microsoft.SqlServer.Dts.Tasks.ScriptTask;
using WinSCP;

namespace ST_5a30686e70c04c5a8a93729fd90b8c79.csproj
{

    public partial class ScriptMain : VSTARTScriptObjectModelBase
    {
        public void Main()
        {
            // Setup session options
            SessionOptions sessionOptions = new SessionOptions
            {
                Protocol = Protocol.Sftp,
                // To setup these variables, go to SSIS > Variables.
                // To make them accessible from the script task, in the context menu of the task,
                // choose Edit. On the Script task editor on Script page, select ReadOnlyVariables,
                // and tick the below properties.
                HostName = (string) Dts.Variables["User::HostName"].Value,
                UserName = (string) Dts.Variables["User::UserName"].Value,
                Password = (string) Dts.Variables["User::Password"].Value,
                PortNumber = 22,
                SshHostKeyFingerprint = (string) Dts.Variables["User::SshHostKeyFingerprint"].Value
            };

            try
            {
                using (Session session = new Session())
                {
                     session.SessionLogPath="G:/Testing/SFTP_Log_Details/winscp.log";
                    // As WinSCP .NET assembly has to be stored in GAC to be used with SSIS,
                    // you need to set path to WinSCP.exe explicitly, if using non-default location.
                    session.ExecutablePath = @"C:\winscp\winscp.exe";

                    // Connect
                    session.Open(sessionOptions);

                    // Upload files
                    TransferOptions transferOptions = new TransferOptions();
                    transferOptions.TransferMode = TransferMode.Binary;

                    TransferOperationResult transferResult;
                    transferResult = session.GetFiles("/my_data/ABC_EMP.txt.zip",@"G:\TestFolder\Download\");

                    // Throw on any error
                    transferResult.Check();

                    // Print results
                    bool fireAgain = false;
                    foreach (TransferEventArgs transfer in transferResult.Transfers)
                    {
                        Dts.Events.FireInformation(0, null, 
                            string.Format("Upload of {0} succeeded", transfer.FileName),
                            null, 0, ref fireAgain);
                    }
                }

                Dts.TaskResult = (int)DTSExecResult.Success;
            }
            catch (Exception e)
            {
                Dts.Events.FireError(0, null,
                    string.Format("Error when using WinSCP to upload files: {0}", e),
                    null, 0);

                Dts.TaskResult = (int)DTSExecResult.Failure;
            }
        }
    }
}

I have generated 'SshHostKeyFingerprint'as "ssh-rsa 2048 9b:63:5e:c4:26:bb:35:0d:49:e6:74:5e:5a:48:c0:8a"

The script task gets executed and failng with below error code "exception has been thrown by the target of an invocation". Log folder is also empty with no log written.