The topic Automatic Update of WSUS OU (v0.9.2.2)
viewtopic.php?f=3&t=374 contains the discussion about Iwan's downloader. See the last few pages. In short, nobody knows, why that domain now requires a login.
You can manually download the current trunk from
http://trac.wsusoffline.net/trac.fcgi/browser/trunk . See the download link at the bottom of the page.
But, if you run into the recent problem with the download of .NET Framework 4.7.2, this doesn't help right now, because trunk wasn't updated yet. Otherwise, the automatic "Update of static download descriptions" would also work. This mechanism is built-in to the script DownloadUpdates.cmd, and it usually takes care of such updates.
Right now, you need to:
- remove the files from wsusoffline/client/md
- manually update the file wsusoffline/static/StaticDownloadLinks-dotnet.txt
- try again