I tried to download files from SFTP path using private key. I used WinSCP user interface. It works fine. But when I tried with Batch file it shows the error as attached. With the guidance of your forum I have created the batch file. When I run it, command prompt shows that authenticated and then starting the session. But after the it shows an error like "connection has been unexpectedly closed server sent command exit status 1. Error skipping startup message. Your shell is probably incompatible with the application (Bash is recommended).
Please refer the screenshot and suggest.