Errors when connecting to HP16550C logic analyzer

I'm trying to connect to a Hewlett Packard 16500C logic analyzer (from 199x) .I can ping the machine using a DOS box, so it is there, but that is a bout it that I can do.
I have included the log file.

IS there anybody out there that knows what is happening? I have the latest version if WinSCP (as per 2019 June).

Thanks in advance.

It's the same problem as here:
https://winscp.net/forum/viewtopic.php?t=7438#26509
or here:
https://winscp.net/forum/viewtopic.php?t=16023#59883