IE11 was definitely working before, but I tried it now and here is console log:
HTML1300: Navigation occurred.
File: login
DOM7011: The code on this page disabled back and forward caching. For more information, see: http://go.microsoft.com/fwlink/?LinkID=291337
File: login
SCRIPT438: Object doesn't support property or method 'assign'
File: frappe-web.min.js, Line: 806, Column: 1