Did you try it with other browsers?
I had no problems with either upgrade on my laptop to Win10 Home or desktop PC to Win10 Pro, It's only after a recent update on my PC with Pro that I can't get past the password screen when logging into Yahoo mail. Filling in my user name/email account works fine but the next screen for my password won't work. I click the "continue" button but nothing happens. This is the only site so far where this happens. Anyone seen this yet?