[exim] relay not permitted message for mailman

Hello,

I must have done something stupid somewhere in the configure file because
when I know need to send a message to a dsitribution list handled by
mailman, mailman gets 550 relay not permitted error message (which was
never the case before).

2007-07-31 10:57:34 H=(lists.lc-words.com) [::1]
F=<test4test-bounces@???> rejected RCPT <someone@???>:
relay not permitted

Can I ask you where to look for the problem. I am not seeing anything
obvious in the configure file and I am really counting on any hint what to
check.

MAILMAN_HOME=/usr/local/mailman
MAILMAN_WRAP=MAILMAN_HOME/mail/mailman

mailman_router:
  driver = accept
  require_files = MAILMAN_HOME/lists/$local_part/config.pck
  local_part_suffix_optional
  local_part_suffix = -bounces : -bounces+* : \
                      -confirm+* : -join : -leave : \
                      -owner : -request : -admin
  headers_remove = X-Spam-Score:X-Spam-Report
  transport = mailman_transport

mailman_transport:
  driver = pipe
  command = MAILMAN_WRAP \
            '${if def:local_part_suffix \
                  {${sg{$local_part_suffix}{-(\\w+)(\\+.*)?}{\$1}}} \
                  {post}}' \
            $local_part
  current_directory = MAILMAN_HOME
  home_directory = MAILMAN_HOME
  user = MAILMAN_USER
  group = MAILMAN_GROUP

hostlist relay_from_hosts = 127.0.0.1 : 192.168.16.4 : MY_IP

The machine with mailman is 192.168.16.4.


Many thanks!

Zbigniew Szalbot