By default, the "passwd" file created by Cygwin when we sync the local users with command "mkpasswd --local > /etc/passwd" includes the machine name in front of the userID. With that setting the authentication tries to connect to the domain controller for the authentication.It is required to modify the <cygwin-Install>/etc/passwd file and remove the "<machine name>+" for the local user account.e.g.,Edit "c:\cygwin64\etc\passwd" file and modify the record for the local userFrom:
NBTEST+Admin:*:197610:197121:U-NBTEST\Admin,<id>:/home/Admin:/bin/bash
To:
Admin:*:197610:197121:U-NBTEST\Admin,<id>:/home/Admin:/bin/bash
Note:It is not required to restart the Cygwin service after you have modified the passwd file.To test the connection, execute command "ssh -l <userID> <machine>" in the Cygwin console.