I am trying to upload a file to an FTP server, but I keep getting the message "Can't build data connection: Connection refused." I have tried it on several FTP servers.

Can anyone tell me what this means?

This is the code that I am using after I have connected:
WSock.SendData "USER username" & vbCrLf
WSock.SendData "PASS password" & vbCrLf
WSock.SendData "STOR textfile.txt" & vbCrLf

Thank you,
JasonTech