This is a bug in Ensim 3.1 that was resolved in 3.1.4, though Ensim has a suggested workaround for earlier versions. The problem occurs when the daily cron jobs are run and logrotate job attempts to restart Apache. this conflicts with the graceful-restart of Apache simultaneously being performed by the /etc/cron.daily/1hup_apache_logs job and the resulting race condition causes Apache to fail entirely and not restart.

The workaround provided by Ensim is to change the command in 1hup_apache_logs from:

/etc/rc.d/init.d/httpd_app_init reload-grc

TO:

/etc/rc.d/init.d/httpd_app_init reload

More information can be found by logging in to Ensim Case Connect and looking up Case 10020: Apache often crashes at night during cron.daily jobs.