Ssh key sync problems between linux server and windows server

[Stephen Carrier]

On Mon, Aug 02, 2021 at 10:08:58AM +0200, Roberto Sabelli via Cygwin wrote:
> Hi everyone, I have this problem that I can't solve:
> 
> I have a linux server (Red Hat Enterprise Linux 6 64bit) and a Windows
> server (Windows Server 2016 Datacenter).
> CYGWIN v. 1.5.22 is installed on the Windows server.
> If I make an SSH connection between the Linux server and the Windows server
> and I try to copy a file from the linux machine to the windows machine
> everything works. If I restart the Windows server and try to connect and to
> copy a file again I get this error:
> 
> *+ ssh username@linuxserver '[ -d /cygdrive/c/pippo/pluto/gio/DS ]’*
> *+ '[' 66 -eq 0 ']’*
> *+ echo '[ERROR] Folder /cygdrive/c/pippo/pluto/gio/DS doesn't exist’*

I don't understand what I'm looking at.  Can you come up with a simple
test case?  Why do the lines end with '*'?  Echoing an 'error message'
will produce an error message but isn't really an error.  I think
folks are baffled.

Reduce to simple test case. 
(such as testing existence of remote directory and nothing else.)
What is the command?
What is the response to the command?

--Stephen