WinSCP and z/OS FTP Server

When I connect using FTP to a mainframe z/OS server and list a unix system services (USS) directory on z/OS it shows as empty even though there are a sub directory with files in it. The directory has 755 as permissions meaning anybody can read and execute. I have tried Google AI suggestions i.e. putting the below in Post-login commands but to no avail.
SITE NAMEFMT 1
SITE LISTFMT 1
CWD /shopz25/

Why does WinSCP not recognize the Unix file structure on z/OS?