How to enable Authentication logging

Hi, I use the basic example to upload file over SFTP.
I'm pretty sure I got all the correct settings like credentials and connections details. I used the same set for the command-line interface (and these are working).
When running the powershell-script I get this error; but I don't see any Authentication log or session log file...

Error: Exception calling "Open" with "1" argument(s): "Connection has been unexpectedly closed. Server sent command exit status 0.
Authentication log (see session log for details):
Using username "XXXXX".
Access denied.

Authentication failed."

You can add logging via: https://winscp.net/eng/docs/library_session

The Session.SessionLogPath should be enough. Do not keep the high logging level and debug log on. That consumes too much resources.