Sometimes it may be necessary to see directly how the openssh daemon reacts to startup or connection requests, to be able to locate daemon-related problems. 

• Stop Openssh SSHD (system name:OpenSSHServer) service

• Right click Start a Unix Bash Shell from Copssh start menu (assuming that you have admin privileges)

• Enter the following command from the bash prompt:

/bin/sshd -p <listening port> -D -d -e

This will start openssh daemon in standalone debug mode and messages will be displayed on the screen. You may specify up to three -d for increased output verbosity.

• Try to initate a putty session and watch messages at the server side.