I am posting this here now, as I did not get any reponse on the
gnus.user list.

I have one folder in my local imap, which I see when I telnet into the
local imap server, which is seen by e.g. Mail (OSX), but not seen by
gnus. I have added the local imap server again as an additional server,
but I also couldn't see it there. It is not killed as far as I can see.

Further details are in the forwarded email below.

Suggestions?

Rainer