If you want to test your WebDAV server as a filesystem with windows, you want to map it as a drive to access it. When you use file:// in the browser, you aren't testing the WebDAV server, just your local hard drive.
To map a WebDAV server on Windows (7, 8, 9, or 10) ...
- Open the windows file manager
- Choose Map a Network Drive (under Home -> Easy access -> map as drive)
- Enter the base URL (https://server.domain.dom/dav) for the WebDAV (same as you used in tiddlywiki but without the filename)
- Check Connect using different credentials
- Use the credentials for the webdav server
If the WebDav server is working properly, you should see it as a mapped drive and be able to use file explorer to read/write files.