#4 Cannot connect via SFTP

[b314]

I am trying to log in to my FTP account that is accessible via SFTP (port 22). With other software (WinSCP) I don't have any problem to connect via SFTP. However, FTPbox just displays a messagebox: "Could not connect .... No suitable authentication method found to complete authentication." (I've checked the firewall, added FTP box as allowed, no influence).
Any clue?
Thanks in advance.
(Platform: Windows 8 Pro / x64, NET 4.5)