Assuming the user/password dialog is successful and you are attempting the GET command, then you get the "Failed to Establish Connection" whiney message, perhaps it is the ftp port number. Sometimes ftp passive ports are range limited, such as using ports 5000-5999. This can be done within your or their router. Either get both ftp's using the same passive port range, or include the command "PASSIVE" within your ftp command dialog.
This passive port limit might be set in /etc/vsftpd/vsftpd.conf
pasv_min_port=5000 pasv_max_port=5999 pasv_enable=YES