That means that you do not yet have a crontab.
to edit (and thus create) it.

To view syntax on the crontab command, and the crontab file itself (as well as cron facility access controls, etc)...
If you want to unschedule your job, either crontab -e, then remove the line containing the job completely, or just comment it out. Else; if that's the only job in your crontab, crontab -r to delete the crontab entirely.


Cheers
ZB