Using the Windows application NetDrive or MacOS X I'm able to access the WebDAV without any fuss, but WinSCP seems to be having an issue of not showing directory contents, though it does get, what - as far as I can see - a correct response to its PROPFIND request. It's the first time I try the WebDAV implementation of WinSCP, so I don't know if it is something new.
Uploading files is no problem, they do get to the WebDAV correctly and are accessible from the iPhone.
The server is running on port 65100 - I've also tried to have it on 80, generating the same result. Though the app also include a secure service, I haven't be using it so far, to keep things as simple as possible.
Version of WinSCP: Version 5.7.5 (Build 5665)
Version of Microsoft Windows: Windows 10 Pro (10.0.10240)
Transfer protocol: WebDAV
GUI or scripting/automation: GUI in Commander interface style