Using what protocol in this test? HTTP or FTP? SSL is an encryption layer over the usual protocol. So using FTP a man-in-the-middle can “see”, read and understand all your bytes and strings flowing in the connection. FTPS encrypts this talk and the content looks like garbage, so, it’s considered “secure”.
When your client side wants to talk to a “host” there you have to have a server counterpart able to understand your encryption layer AND protocol. Both sides MUST be compatible.
That said, FTP (and FTPS) and SFTP are different beasts. 
FTPS is a FTP protocol with encrypted content. It’s served by a File server serving FTP, ports varies for clear or encrypted, and 2 channels are used, data and control. Usually 21 for command, and other for data (default 20, but it changes)
SFTP is served by a File server serving through SSH in a bidirectional encrypted tunnel usually in port 22.
It’s common people with a FTP server having problems trying to use SFTP client (SSH server not present) and the inverse, having a SSH server and trying to access it using a FTP client. Both cases is a no-no.