I had an issue where I had cron jobs that output data to stdout, yet mail of the output was never delivered. Everything showed fine in cron.log :

Aug  3 21:21:01 mail CROND[10426]: (nicholas) CMD (echo “test”)
Aug  3 21:21:01 mail CROND[10424]: (nicholas) CMDOUT (test)

yet no e-mail was sent. I finally found out how to fix this in a roundabout way. I came across this article on cpanel.net on how to silence cron e-mails. I then thought I’d try the reverse of a suggestion and add MAILTO= variable at the top of my cron file. It worked! Example crontab:

MAILTO=”youremail@address.com”
0 * * * * /home/nicholas/queue-check.sh

This came about due to my Zimbra box not sending system e-mails. In addition to the above, I had to configure zimbra as a sendmail alternative per this Zimbra wiki post: https://wiki.zimbra.com/wiki/How_to_%22fix%22_system%27s_sendmail_to_use_that_of_zimbra