error logging into ftp server

[dragonember]

I set up an FTP server on my linux box so my friends can log in and take the files they want. (not anything illegal, pictures i took, code we are working on, stuff like that). I used this command to start the server:pure-ftpd -S xxx.xxx.xxx.xxx,21 -c 30 -C 1 -l puredb:/etc/pureftpd.pdb -x -E -j -R

when i try to log onto the server by using the command "ftp xxx.xxx.xxx.xxx" i get :

Connected to xxx.xxx.xxx.xxx (xxx.xxx.xxx.xxx).
220---------- Welcome to Pure-FTPd [privsep] [TLS] ----------
220-You are user number 1 of 30 allowed.
220-Local time is now 00:16. Server port: 21.
220-This is a private system - No anonymous login
220-IPv6 connections are also welcome on this server.
220 You will be disconnected after 15 minutes of inactivity.
Name (xxx.xxx.xxx.xxx:user): example
331 User example OK. Password required
Password:
421 Service not available, remote server has closed connection
Login failed.
No control connection for command: Permission denied

I have no idea whats wrong here. I did allow it through the firewall (obviously). does anyone know how to solve this??

the xxx.xxx.xxx.xxx is my ip address, I just don't want to post it online