A bit of background:
The target server is a VM running under Oracle VirtualBox on my workstation.
Yesterday my workstation was upgraded from Windows 7 Pro to Windows 10.
Prior to the upgrade I had no problem making this connection to this VM.
After the upgrade of the workstation to Win 10, I had to re-install WinSCP. I now have 4.3.7 and do not know what version I had prior.
I also have several VMs running Linux and have no problem getting a WinSCP connection to them.
I am using the default port/protocol of 22/sftp. If I change to 21/ftp, it will at least prompt for username/pswd, but still returns with 'access denied'. If using 22/sftp it does not even prompt for credentials. In neither case am I supplying credentials as a property of the connection definition.
The firewall on the target server is turned off.