cyrus sieve notify can't work !

[Brasseur Valéry]

I am trying to use sieve notify but have no success.
here is my sieve script :
------------
require "notify";

if header :contains "from" "someuser at somedomain.com" {
        notify :message "bonjour!";
        redirect "postmaster at segin.com";
}
------------

when receiving a mail the redirect is working but the notify is not done !

what's wrong ?

thanks
valery