cron job qiestions

I have script that sends an email every time I run the script. I setup cron job with that script as follows.
#crontab -e
added as following to run every 5mins.
*/5 0 * * * /usr/local/bin/sysmon
I checked cron is running. But I'm not getting any emails as I get it when I run manually. Any ideas.
Thanks.

The way you wrote it, it will run every five minutes, between midnight and 1 am. Change the line to

*/5 * * * * /usr/local/bin/sysmon

and everything should be fine.