FTP file upload not work in server

I have create a file upload project in silverlight using FtpClient by following this link (https://github.com/dittodhole/sharpLightFtp).

It works well in local development(visual studio) and local iis server also.But when I host this into my server i get following problem.

var success = ftpClient.BasicConnect();

success becomes false.What may be the reason for this?