can not receive emails sent to the mailing list

I need help regarding Mailman on ISPConfig 3.
I used a tutorial that is in http://www.howtoforge.com/perfect-server-ubuntu-12.04-lts-apache2-bind-dovecot-ispconfig-3-p7.
I'm using Ubuntu 12:04, ISPConfig 3.0.4.5, Mailman version 2.1.14.
I found the problem when I try to send to the address mailling list has been created can be sent but a member of the mailling list can not receive the error from the logs as follows:

root@mail:~# tail -f /var/log/mailman/error
mlist.ArchiveMail(msg)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 198, in ArchiveMail
self.__archive_to_mbox(msg)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 167, in __archive_to_mbox
mbox = self.__archive_file(afn)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 155, in __archive_file
return Mailbox.Mailbox(open(afn, 'a+'))
IOError: [Errno 13] Permission denied: '/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox'

May 20 23:39:33 2012 (16713) SHUNTING: 1337571572.222312+9f291efb586db2febf5305a5db0eaa67bbe34acf
May 20 23:41:06 2012 (16713) Archive file access failure:
/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox [Errno 13] Permission denied: '/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox'
May 20 23:41:06 2012 (16713) Uncaught runner exception: [Errno 13] Permission denied: '/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox'
May 20 23:41:06 2012 (16713) Traceback (most recent call last):
File "/var/lib/mailman/Mailman/Queue/Runner.py", line 120, in _oneloop
self._onefile(msg, msgdata)
File "/var/lib/mailman/Mailman/Queue/Runner.py", line 191, in _onefile
keepqueued = self._dispose(mlist, msg, msgdata)
File "/var/lib/mailman/Mailman/Queue/ArchRunner.py", line 73, in _dispose
mlist.ArchiveMail(msg)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 198, in ArchiveMail
self.__archive_to_mbox(msg)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 167, in __archive_to_mbox
mbox = self.__archive_file(afn)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 155, in __archive_file
return Mailbox.Mailbox(open(afn, 'a+'))
IOError: [Errno 13] Permission denied: '/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox'

May 20 23:41:06 2012 (16713) SHUNTING: 1337571665.560379+e108bae3671a958fb2aaa36ae46272ffae6feded

 

The following results:

root@mail:~# ls -la /var/lib/mailman/archives/private/
total 24
drwxrws--- 6 list www-data 4096 May 20 22:23 .
drwxrwsr-x 4 root list 4096 May 20 07:04 ..
drwxrwsr-x 2 root www-data 4096 May 20 22:23 devlop
drwxrwsr-x 2 root www-data 4096 May 20 22:23 devlop.mbox
drwxrwsr-x 2 root www-data 4096 May 20 07:06 mailman
drwxrwsr-x 2 root www-data 4096 May 20 07:06 mailman.mbox
root@mail:~# ls -la /var/lib/mailman/archives/private/devlop.mbox/
total 8
drwxrwsr-x 2 root www-data 4096 May 20 22:23 .
drwxrws--- 6 list www-data 4096 May 20 22:23 ..
root@mail:~#

 

I try to test changing the file permissions as below can not be as well.
And I check the file is not found, but why the results of the "tail-f / var / log / mailman / error: his permission to say no?
what should i do to solve this problem?

root@mail:~# tail -f /var/log/mailman/error
mlist.ArchiveMail(msg)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 198, in ArchiveMail
self.__archive_to_mbox(msg)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 167, in __archive_to_mbox
mbox = self.__archive_file(afn)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 155, in __archive_file
return Mailbox.Mailbox(open(afn, 'a+'))
IOError: [Errno 13] Permission denied: '/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox'

May 22 08:00:48 2012 (1828) SHUNTING: 1337688047.222328+cf711499df2ccfeb0a0c9a1537f8c4eb196a06c1
May 22 08:03:24 2012 (1828) Archive file access failure:
/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox [Errno 13] Permission denied: '/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox'
May 22 08:03:24 2012 (1828) Uncaught runner exception: [Errno 13] Permission denied: '/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox'
May 22 08:03:24 2012 (1828) Traceback (most recent call last):
File "/var/lib/mailman/Mailman/Queue/Runner.py", line 120, in _oneloop
self._onefile(msg, msgdata)
File "/var/lib/mailman/Mailman/Queue/Runner.py", line 191, in _onefile
keepqueued = self._dispose(mlist, msg, msgdata)
File "/var/lib/mailman/Mailman/Queue/ArchRunner.py", line 73, in _dispose
mlist.ArchiveMail(msg)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 198, in ArchiveMail
self.__archive_to_mbox(msg)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 167, in __archive_to_mbox
mbox = self.__archive_file(afn)
File "/var/lib/mailman/Mailman/Archiver/Archiver.py", line 155, in __archive_file
return Mailbox.Mailbox(open(afn, 'a+'))
IOError: [Errno 13] Permission denied: '/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox'

May 22 08:03:24 2012 (1828) SHUNTING: 1337688202.511744+fa06232779f46525021420748bde3c6a33949077
^C^X^C
root@mail:~# chmod +x /var/lib/mailman/archives/private/devlop.mbox/devlop.mbox
chmod: cannot access `/var/lib/mailman/archives/private/devlop.mbox/devlop.mbox': No such file or directory
root@mail:~# chmod +x /var/lib/mailman/archives/private/devlop.mbox
root@mail:~# cd /var/lib/mailman/archives/private/devlop.mbox/
root@mail:/var/lib/mailman/archives/private/devlop.mbox# ls
root@mail:/var/lib/mailman/archives/private/devlop.mbox#