Insecure cron table permission
A cron table is rejected if its permission is insecure
sudo service cron restartgrep -i cron /var/log/syslog|tail -22013-02-05T03:47:49.283841+01:00 ubuntu cron[49906]: (user) INSECURE MODE (mode 0600 expected) (crontabs/user)The problem is solved with
# correct permissionsudo chmod 600 /var/spool/cron/crontabs/user# signal crond to reload the filesudo touch /var/spool/cron/crontabs
