My issue is gone in a magical way:
Yesterday Night I installed 7.0.0. of StreamDeck, and made some Windows Updates. Frustrated I went to bed. This Morning I want to search again for a Solution and the issue was gone and the stream deck was working again.
I does Not Change anything Else, so I think it was a bug in a windows update.
Exactly the same here, yesterday everything works.
Now I Am searching for Hours, nothing Helps and everything seems to work.
But no Connection from SD to AAO, Ports Change, Clean Install, Windows Defender Check, Port forewarding, nothing helps.