Using this knowledge, I tried this, and it does seem to fill in missing tracks and is able to query again. But despite the server’s responses being identical to those on Windows 10, the album art doesn’t seem to download.
I have access to a Windows 7-era version of the requests and the album art seems to be done by a relative path instead of an absolute path like it is now, but it’s not clear how it works exactly. Lots of other free tools to grab album art for your music files though.
If you want to try it yourself, add:
198.46.168.75 redir.metaservices.microsoft.com to your hosts file.