unsubscribing doesnt work

[John]

Hello,

unsubscribing should work well, by sending an email to 
[EMAIL PROTECTED]

is't it?

I tried about 3 times, but i get "This is the Postfix program at host 
fmmailgate02.web.de"
i.e. the email could not be sent.
However, do i do anything wrong?

Regards.
John