Cannot you show us the hostname?
Here is the putty log ...
Please attach the PuTTY log too.
The putty log is not meaningful, I have two identical servers (one works WinSCP with name one not) I attach both log files. It seems WinSCP is not using DNS servers.
Please attach a complete WinSCP session log file as well as PuTTY event log.
I'm using WinSCP with version 5.13. When I try to connect from the GUI to a server over SFTP port 22 it only works when I enter the IP address, but not with the server name. DNS resolution works without any issue on the server. I have no problem to connect to other apps like putty with name. Anyone has the same issue?