FTP An existing Connection forcibly closed by the remote host

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C#

Hi,

I am getting an error as "An existing connection was forcibly closed by the remote host."

I am not sure FTP server has open the port 990.

my code as follows

FtpWebRequest request = null;
FtpWebResponse response = null;

request = (FtpWebRequest)WebRequest.Create(new Uri("ftp://ftp.example.com:990"));

request.UsePassive = true;
request.Method = WebRequestMethods.Ftp.ListDirectory;
request.Credentials = new NetworkCredential(username, password);
request.Proxy = null;
request.EnableSsl = true;
request.UseBinary = false;
request.KeepAlive = false;

request.Timeout = int.MaxValue;
request.ReadWriteTimeout = int.MaxValue; //10000000;
response = (FtpWebResponse)request.GetResponse();

But i am able to access through CoreFtp by using port 990 and while using CoreFtp to connect to FTP server it pops up a window which has Server certificate if i accept the certificate then i am connected to the FTP server.
Please help me what is the issue i am trying for this for couple of days.

How to handle the FTP server certification in my C# program?
I am getting error while getting response, i.e, request.GetResponse().
I am not sure the connection is established or not.

Thanks in advance