Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.6.2

Error message:
Error listing directory '/root'.

Unexpected directory listing line ''.
Range check error

Stack trace:
[01936015]
[01937548]
[017D353E]
[017E0496]
[017DFE50]
[01867515]
[01864765]
[018666A4]
[0185FD48]
[017CBAE3]
[017C5844]
[011E18B7]
[77443388] kernel32.dll.BaseThreadInitThunk
[77D29900] ntdll.dll
[77D298D0] ntdll.dll

Status: symbol_unknown

I know how to reproduce the problem or the problem happens frequently enough. I wish to be contacted by the WinSCP team to help resolving the problem.