In general, the remote path should use forward slashes, not backslashes.
See also Why I cannot connect/transfer using script, when I can using GUI (or vice versa)?

Hi everyone,
When we are trying to sync remote directory via command line, We are getting an error "Error Listing the directory, Permission denied", whereas if we are using the WinSCP GUI it is working fine.

Just for the reference the same code was working since last 2 months and all of a sudden it stopped working.

PFA the screenshot.

Thanks