Dear Support,
I did all the steps, which you mentioned about configuration of FTP.My port checking is success.But still i couldnt login.Even i put correct login information ,still asking username and password.Kindly help me to solve this issue

If you are able to connect to ftp://yourhostname.dynu.com and get the username and password prompt, then the port forwarding and dynamic DNS are set up correctly.

The username and password are created by you on your Filezilla server.