When downloading a virtual machine at https://dev.windows.com/en-us/microsoft-edge/tools/vms/ I'm always getting a Unknown network error from my browser, in this case chromium. But I had the same experience with iceweasel.
I don't know why this happens. There are some posts that say the browser didn't like so big files, but I guess the problem is maybe on the server side.
If you want to bypass this problem you can download the file with wget on Linux. wget has also some problems with that file, but it restarts the download process after every break from the last point. Just copy the link of the file and download it with wget.