Could this be because I up grader WIN10 to 2004?
This is unheard of but, it's possible depending what the update did in your case. Surely reinstalling Windows from scratch would require a reactivation, upgrading shouldn't.
In any case, as explained many times on the forum, and on all product manuals, you should never post questions about activation on the forum, and use the support email instead. Because, we next question would have been "what's is your key", and we cannot discuss it here.