ConnectionClosed Error 1002 at ftp.upload

[Someone]

I'm getting the error 1002 (ConnectionClosed) when I run my project.
The server address is correct and and doesn't start with ftp:\\. At the upload funtion I get the ConnectionClosed Error

sf::Ftp::Response res = ftp.upload(totalPath, "Game11/System", sf::Ftp::Binary);

[eXpl0it3r]

And is the server running FTP and not SFTP or FTPS?