@micoscas: Ok, so you have completely different problem that this thread is about.
So can you connect to that host any other way? Using any other client using the same protocol?

Hi,
I mean that I get the same error "Host XXX does not exist" in the version 5.X (I do not remember exactly what was the version)
I upgraded to the version 6.1.2 but still get the error.
I receive this error whether it is when running my code or the WinSCP program.
Regards,
Michael

@micoscas: What "same issue"? Was it working with some older version (which?) and now it does not?

Hi,

I an facing to the same issue, working with the last version 6.1.2.
I am connecting via DNS server name that points on 3 different addresses, none has leading zero

I will happy to get some help :)

Thx,
Michael

Thank you,
removing the leading 0 fixed the issue so the ticket can be closed.

Kind regards,
Paolo

Thanks. It's because of the leading zero in .01 in your IP address. Apparently, it's a side effect of this commit in PuTTY SSH code:
Reorganise sk_namelookup (on both platforms)
I'll look into it. Meanwhile, just remove the zero. It probably should not be there in the first place. Use of leading zeros in IP addresses seem to be debatable and confusing.
Note that the previous version interpreted the leading zero as an octal prefix. So while 01 (octal) is still 1 (decimal) – what is understandable – for an example a 036 (octal) would be 30 (decimal) – what would be confusing.
See also Is 192.056.2.01 a valid representation of an v4 IP?

Hi Martin,
thank you for your reply.
I uninstalled WinSCP 6.1, installed the previous working version (5.21.8) and confirmed that I can access the host.
I then upgraded again to 6.1 and the issue reappeared ("host does not exist").

Please find attached the log files.

Please post session log file. Also, can you downgrade to the version you were using previously and post its log file too? You can download older versions of WinSCP from:
https://sourceforge.net/projects/winscp/files/WinSCP/

I have been using WinSCP to connect to a machine on our network for months.
This morning I was prompted to update to 6.1, which I did.
After the update, WinSCP is unable to find the host.
I can connect to the host via SSH from a shell, I can connect from Visual Studio, so the host is definitely on.
The IP address has not changed and in fact WinSCP still has the address in memory, so it is not a matter of having a typo.
I checked Windows firewall and there is nothing preventing WinSCP from connecting.
At this point I am lost. Any help would be appreciated.

Kind regards,
Paolo