Thanks for sharing your experience. When I went through this, it was a brand-new computer that my in-laws had purchased off of Amazon. We were thinking about sending the whole thing back over this problem. The last thing I wanted to do was reinstall Windows, that was sorta the whole purpose of buying a new computer, was to not need to do that. There should be no reason to reinstall Windows on a new computer, and if you were going to reinstall, why would you install bloody Windows S mode, which is the very thing that's giving problems (unless that's the only copy you had, I guess that would be a good reason).
But anyway, I'm not even sure that reinstalling Windows is guaranteed to work. It feels like this is just a random thing. It almost feels like there is a problem with the Microsoft servers that process the S mode requests, which causes it to just be flakey.