[bitfolk] Cannot connect to console with PuTTY

I've just installed PuTTY on a new PC running Windows 10. When I attempt to connect to my VPS console (on bellini) PuTTY immediately disconnects with the message "Disconnected: No support authentication methods available (server sent: publickey,keyboard-interactive)" I can connect to my VPS using PuTTY without any problems. I can also connect to the console on bellini from my home Linux box (using openssh on CentOS 6). This was working (PuTTY, Windows 10) a couple of weeks ago - has anything changed? Thanks, Mike