I have Firefox now, Marco and the solution is simple.
Go to the internet tools and choose "privacy" (in German it's "Datenschutz") Delete your cookies and the files in the cache and restart the browser. Now you can login.
Firefox is so much better and faster than IE, I am happy to have it. Only Microsoft and QOL (!!) do not work with Firefox and some websites look ugly but are usable.
I do not want any google ads here.