Connect external FTP-server using FTP proxy

[#1]

Hi!

We try to establish connect with external FTP server using FTP Proxy settings in sender channel.

We have approval that we should use USER@HOST proxy type. Proxy host is reachable. User credentials for target FTP server are also correct. FTP proxy doesn't use authentication.

But when we try to connect we get error: "The URL ftp://our_user@our_ftp_server/ needs authentication"

What might be the reason for this error?

Regards, Evgeniy.