[Mailman-Users] mail server cannot communicate with mailman

[George Argyros]

Hi all,
I am trying for some days now to setup mailman in debian but i am
running to the following problem:
Although mailman setup seems fine and the mail server (Exim or
Postfix) can send mail to any address, mailman and the mail server
cannot communicate. Every time i try to post a message to a list, or
send a password reminder from mailman etc. the mails never reach their
destination, and usually i get an error after some time.
As i mention above i tried both Exim and Postfix and ran into the same
problem. I have installed mailman from the repositories and as a web
server i use apache 2.
I would appreciate any suggestions on the problem.
Thanks in advance,
George