How do you write a cron expression? 5-field and 6-field forms
Cannot make sense of 0 0 * * *? Split the fields and look at the next run times instead.
The scenario
The field order of crontab / CronJob is easy to mix up. Five fields mean "minute hour day month weekday"; six fields add seconds in front.
0 0 * * * means "at 00:00 every day". Use the cron parser to get a plain-English explanation and the next run times.