Is this information helpful to post to the list or should I post this as a new bug report. I couldn't tell if a bug report was already out there at https://bugs.launchpad.net/mailman related to this issue. Thanks. Bug in Mailman version 2.1.15 We're sorry, we hit a bug! Please inform the webmaster for this site of this problem. Printing of traceback and other system information has been explicitly inhibited, but the webmaster can find this information in the Mailman error logs. I copied this from var/lib/mailman/logs/error [root@pogo logs]# grep 16339 error Sep 03 13:33:37 2013 admin(16339): @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ admin(16339): [----- Mailman Version: 2.1.15 -----] admin(16339): [----- Traceback ------] admin(16339): Traceback (most recent call last): admin(16339): File "/usr/lib/mailman/scripts/driver", line 112, in run_main admin(16339): main() admin(16339): File "/usr/lib/mailman/Mailman/Cgi/subscribe.py", line 99, in main admin(16339): process_form(mlist, doc, cgidata, language) admin(16339): File "/usr/lib/mailman/Mailman/Cgi/subscribe.py", line 179, in process_form admin(16339): mlist.AddMember(userdesc, remote) admin(16339): File "/usr/lib/mailman/Mailman/MailList.py", line 897, in AddMember admin(16339): cookie = self.pend_new(Pending.SUBSCRIPTION, userdesc) admin(16339): File "/usr/lib/mailman/Mailman/Pending.py", line 87, in pend_new admin(16339): self.__save(db) admin(16339): File "/usr/lib/mailman/Mailman/Pending.py", line 107, in __save admin(16339): timestamp = evictions[cookie] admin(16339): KeyError: 'one_last_digest' admin(16339): [----- Python Information -----] admin(16339): sys.version = 2.7.5 (default, May 17 2013, 23:45:32) admin(16339): sys.executable = /usr/bin/python2 admin(16339): sys.prefix = /usr admin(16339): sys.exec_prefix = /usr admin(16339): sys.path = ['/usr/lib/mailman/pythonlib', '/usr/lib/mailman', '/usr/lib/mailman/scripts', '/usr/lib/mailman', '/usr/lib/python27.zip', '/usr/lib/python2.7/', '/usr/lib/python2.7/plat-linux2', '/usr/lib/python2.7/lib-tk', '/usr/lib/python2.7/lib-old', '/usr/lib/python2.7/lib-dynload', '/usr/lib/python2.7/site-packages'] admin(16339): sys.platform = linux2 admin(16339): [----- Environment Variables -----] admin(16339): HTTP_REFERER: http://mail.a2-16v.com/mailman/listinfo/a2-16v-list admin(16339): SERVER_SOFTWARE: Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/1.0.1e DAV/2 PHP/5.4.16 admin(16339): SCRIPT_NAME: /mailman/subscribe admin(16339): SERVER_SIGNATURE: <address>Apache/2.2.24 (Unix) mod_ssl/2.2.24 OpenSSL/1.0.1e DAV/2 PHP/5.4.16 Server at mail.a2-16v.comPort 80</address> admin(16339): admin(16339): REQUEST_METHOD: POST admin(16339): PATH_INFO: /a2-16v-list admin(16339): HTTP_ORIGIN: http://mail.a2-16v.com admin(16339): SERVER_PROTOCOL: HTTP/1.1 admin(16339): QUERY_STRING: admin(16339): CONTENT_LENGTH: 85 admin(16339): HTTP_USER_AGENT: Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.57 Safari/537.36 admin(16339): HTTP_CONNECTION: keep-alive admin(16339): SERVER_NAME: mail.a2-16v.com admin(16339): REMOTE_ADDR: 144.160.98.31 admin(16339): PATH_TRANSLATED: /srv/http/a2-16v-list admin(16339): SERVER_PORT: 80 admin(16339): SERVER_ADDR: 192.168.1.150 admin(16339): DOCUMENT_ROOT: /srv/http admin(16339): PYTHONPATH: /usr/lib/mailman admin(16339): SCRIPT_FILENAME: /usr/lib/mailman/cgi-bin/subscribe admin(16339): SERVER_ADMIN: chadrebuck@gmail.com admin(16339): HTTP_HOST: mail.a2-16v.com admin(16339): HTTP_CACHE_CONTROL: max-age=0 admin(16339): REQUEST_URI: /mailman/subscribe/a2-16v-list admin(16339): HTTP_ACCEPT: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 admin(16339): GATEWAY_INTERFACE: CGI/1.1 admin(16339): REMOTE_PORT: 34727 admin(16339): HTTP_ACCEPT_LANGUAGE: en-US,en;q=0.8 admin(16339): CONTENT_TYPE: application/x-www-form-urlencoded admin(16339): HTTP_ACCEPT_ENCODING: gzip,deflate,sdch admin(16339): UNIQUE_ID: UiYdcH8AAAEAACPeG6gAAAAI