Connects, but client closes connection

I'm trying to connect via SFTP. The connection seems to connect, but after a few seconds the client will close the connection and displays the following error:

[05:36:59] SmartFTP v2.0.999.5
[05:36:59] Resolving host name ""
[05:36:59] Connecting to Port: 22
[05:36:59] Connected to
[05:36:59] SSH-1.99-Pragma FortressSSH
[05:37:39] Timeout (40s).
[05:37:39] Active Help:
[05:37:39] Client closed the connection.
[05:37:39] Cannot login waiting to retry (30s)...

I've used SFTP.exe from the putty suite, and it works fine, as well as Filezilla and winscp, but I'd rather use smartFTP. It is the best one, in my opinion. I've also tried using both explicit and implicit mode, but it will not work either. Any help would be appreciated. Thanks!

SmartFTP does not (yet) support SFTP, only FTPS.

SmartFTP does not (yet) support SFTP, only FTPS.

Thanks. I didn't know they are two different things.