I'm sorry it was the proftpd crap ftp server... it seems they do what they want, and in some points they don't care about FTP standards... maybe it's possible to configure it until it's compatible, but maybe you need many days or weeks for that. E.g. Foscam Cameras (they wrote that entry i talk about, but the problem was on "proftpd" side) are COMPLETELY incompatible to it.
Maybe you can confirm me, as the developer of WinSCP, that "proftpd" needs some special handlings for FTP client app- or library-programmers? (and progammers they use FTP libraries...?
On M$ FTP i NEVER had such am mess compared to proftpd when i used the free version if https://enterprisedt.com/products/edtftpj/,
but with "proftpd" i needed hours (maybe an afternoon) of try-and-error to make it work...)
But i also know that plesk is also using "proftpd", but they have a LOT of money for engineers they customize proftpd to make it well compatible - we (a small company) so we don't have that.
It seems that every company has its own view of "FTP standards" - but in fact, it's cleary defined how it works. It exists since 1985, but the IT community seems to be completely unable to make it right!?
But your WinSCP is very very nice, best Tool for FTP / SCP / SFTP!! :-)
-> On your FTP client, i it has shown that entry, on File Zilla and the SSH console just an empty line...
Now we use "vsftpd", and all works well. "proftpd" is died for me now!!