I finally got it to work.....
At least it was a little bit weird. But it works now.
Finally I tried to connect over and over again up to that point when I got the "Bad Message 431" message. From that point I never found a way to move on.
This time I copied the entire link, stated in the top of the window and opened this link in a new browser window again. Voila that did the trick. I just connected Home Connect to my HE and got my dishwasher listed.
Thanks
