Hi @Ralf Longwitz , is this the button you're using to sign in?
if so when you attempt to sign, does it open your browser? Are you able to sign in there, where it says "you have signed in, you may close this window?" And then you're still not signed in in VS Code? Or does nothing come up? I'm trying to see where this breaks.
You could always try re-installing VS Code too to see if it works, couldn't hurt!
Please let me know and I can help you further.
Best,
James