Many thanks in advance.
EDIT: If it helps, I am getting things like the following in /var/log/httpd/error_log
but not sure that that gives me any clues![Fri Feb 05 17:55:28 2010] [error] [client xxx.xxx.xxx.xxx] ModSecurity: Unable to retrieve collection (name "ip", key "xxx.xxx.xxx.xxx"). Use SecDataDir to define data directory first. [hostname "webmail.domain.com"] [uri "/services/portal/sidebar.php"] [unique_id "KCfPQFLFTwQAABUsUXcAAAAN"]
EDIT 2: Then suddenly it started working and we did nothing. Can anyone suggest what was causing this? The only other entry I found that may give me a clue is:
[Fri Feb 05 18:01:34 2010] [warn] Init: You should not use name-based virtual hosts in conjunction with SSL!!
[Fri Feb 05 18:01:34 2010] [notice] mod_python: Creating 4 session mutexes based on 256 max processes and 0 max threads.
[Fri Feb 05 18:01:34 2010] [notice] Apache/2.2.3 (CentOS) configured -- resuming normal operations