HI try to do the followings
1. Check the ftp host address,and config file for updating server details
2. Alos check the credentials , if no permission then also file will not get uploaded to server
ftp.Credentials = new NetworkCredential("userid", "password");
3. While creating FtpWebRequest.Create why you are passing Session ID please check, and try to do as below
string ftpfullpath = "ftp://" + ftphost + ftpfilepath;
FtpWebRequest ftp = (FtpWebRequest)FtpWebRequest.Create(ftpfullpath);