At first, I couldn't login using IE11. I had to use Chrome.
Oddly, after the initial login with Chrome, IE11 worked for me on both Win7 and Win10. I remember clearing the browser files (i.e. temporary Internet files, etc. ) on the Win10 PC before IE11 worked, but can't confirm that's what fixed the issue. This post was done using IE11.
I know some folks have tried clearing the browser files, but still aren't able to use IE11.