You (oracle) are not allowed to use this program (crontab)

error while checking crontab details as oracle user

[oracle@dbracnode02 ~]$ crontab -l
You (oracle) are not allowed to use this program (crontab)
See crontab(1) for more information

Check entries in /etc/cron.allow

[root@dbracnode02 ~]# cat /etc/cron.allow


To solve this error you should add oracle or any other users that will use the Crontab into this file as follows.

Add oracle user and save /etc/cron.allow
[root@dbracnode02 ~]# vi /etc/cron.allow
root
oracle
grid

[root@dbracnode02 ~]# cat /etc/cron.allow
root
oracle
grid

Check now:
[oracle@dbracnode02 ~]$ crontab -l
no crontab for oracle