Is it possible to use OpenSSL with your ftp.ddl project? I was just wondering because I get an handshake error using AUTH SSL on ftp server's which use OpenSSL.
No, it is not possible. OpenSSL would not solve your problem anyways.
The handshake failed error most likely mean that your server requires explicit SSL. Use the following code to connect:
client.Connect("ftp.example.com"); client.AuthSSL(); client.Login("username", "password")
You can find more information here: https://www.limilabs.com/blog/the-handshake-failed-due-to-an-unexpected-packet-format-ftp