When connecting, error:1408F10B:SSL routines:ssl3_get_record:wrong version number

Hello,

Recently a third-party company has changed its configuration and is now requiring to use FTP with an explicit encryption. So far so good, I adapted configuration on my side, but can't succeed to connect to their FTP. The error I get using the GUI program being

SSL3 alert write: fatal: protocol version
Disconnected from server
Could not retrieve directory listing
Error listing directory '/data'.

I have updated WinSCP to version 5.21.1, it doesn't help but the message is now different:

SSL3 alert write: fatal: protocol version
wrong version number
An established connection was aborted by the software in your host machine.

When using FileZilla (an old version, from 2018. I have troubles getting an up to date version, but that's off topic), everything is fine and I can download the file I need. This brings me to the conclusion that there is something wrong with the way I try to connect to the FTP with WinSCP, but I don't know what. You can find in attachment both logs using WinSCP and FileZilla. The only additional error message I can see from the log is the following:

error:1408F10B:SSL routines:ssl3_get_record:wrong version number

I have searched on Internet what could be the reasons for such an error, but nothing was of any help. Do you have any idea of what's going on?

With many thanks in advance, I wish you to have a nice day!

Sorry, no idea. As it is a third-party company, I assume that there's no chance to get a test account on the server, right?

Hi. We can ask to get an account, maybe they will agree.
Before to ask, are we speaking about an account with exactly the same configuration as the one we use, but for you to test what's happening?

Yes. Thanks.

Hi,

Sorry for the delay of answer. I don't think you will have a test account, they did answer by giving new credentials using SFTP protocol.

Julien