Cannot Connect to Secure FTP Server

[fiondatroy]

i'm trying to log into a secure ftp server. it uses core ftp server software. i am behind a firewall. i am using windows xp sp2 and the windows firewall is off.

when i try to connect, i get the following message:
220 Serv-U FTP Server v5.2 for WinSock ready...
AUTH SSL
234 AUTH command OK. Initializing SSL connection.
SSL/TLS error - 0, SSL error - 1
SSL Connection not established

i am able to connect to this server from a computer that is not behind our firewall, so i my thinking is that there is some configuration with our firewall that is not allowing the connection.

i am using core ftp lite ver 1.3b, build 1391 (U)

[fiondatroy]

we are using a watchguard firebox. i checked and it said

This is a problem because the FTP control connection specifies which ports will be opened for the FTP data channel. When the control connection is encrypted, there is no way that any firewall or NAT device can successfully examine (for opening the ports) or rewrite (for NAT) the contents of the control connection. This makes it difficut to pass SSL FTP through the Firebox (or any other NAT or firewall device).

it recommended trying some other clients, which prove unsuccessful as well.

i also upgraded to the latest version as you suggested and get the same response.

i was mistaken on the server they are using, it is SERV-U FTP Server.

If you have any other suggestions, i would be very grateful. thanks.