Can't trigger update existing score from my PC.

I’m trying to updte an existing score without losing my statistics on Musescore.com. I’ve grabbed the link of the score from musescore.com with the 'share' button. I’ve copied and pasted the link into File > Score properties > source in MuseScore on my PC s and that link is correct.. When I try to save on-line, I should be seeing "update existing score" check box… but I don’t and it creates a new score. Any suggestions? on how to get the check box?
I have attached screen shots.