If you use the options link to disable a user, sometimes they are not removed from the mailing list.
The thing to do is to check that the root
user can list users. Do:
su - root /export/home/mailman_1/bin/find_member cxbrooks@gmail.comYou should the mailing lists to which the user belongs. If you don't, then there are problems with the mailman or the path of the root user I had to create a link:
ln -s /usr/local/bin/python /usr/bin