On the SSH Open action, turn on Verbose logging and post the log output so we can see what is going on. I assume you have generated a key pair on your mac using something like this :
What authentication methods are allowed on your SSH server. FinalBuilder only supports password or public key. If the privatekeyfile property is set then it will use private key, otherwise it will use password authentication. With putty, my guess is it’s using keyboard-interactive authentication. You will need to configure the SSH server to allow password authentication.