Fillezilla client not working with Filezilla server.

[chrisc_w]

We have two filezilla servers active, one is hosted locally here and is version number 0.9.43 and the other is hosted in AWS and is server version 0.9.60. Bother servers are set the same as far as possible. Both servers work fine with CuteFTP and ClassicFTP. The one hosted internally here will work with Filezilla client, the one hosted in AWS will not connect with filezilla client. Here are the messages that get sent and received:

Status: Connecting to n.n.n.n:21...
Status: Connection established, waiting for welcome message...
Response: 220-Welcome to the Wicks and Wilson FTP site.
Response: 220-
Response: 220 Part of the Crowley group
Command: AUTH TLS
Response: 502 Using authentication type TLS
Command: AUTH SSL
Error: Could not connect to server
Status: Waiting to retry...
Status: Connecting to n.n.n.n:21...
Status: Connection established, waiting for welcome message...
Response: 220-Welcome to the Wicks and Wilson FTP site.
Response: 220-
Response: 220 Part of the Crowley group
Command: AUTH TLS
Response: 502 Using authentication type TLS
Command: AUTH SSL
Error: Could not connect to server

I have tried a few tweaks of both server and client but to no avail, the AWS hosted FTP server still works with other clients but not with Filezilla.

[botg]

There is a malicious firewall or NAT router sitting between the client and the server that is actively sabotaging the connection.

[boco]

Consider updating the old server version, it is vulnerable.