When the linux os installed on the system two kinds of file created to configure crontab one is called cron.allow and other one is cron.deny
If it is not present in the server crontab utility throws not allowed to use this program error when the user try to use crontab.
To solve this error system admin need to create cron.allow & cron.deny files to add the user to access or deny crontab utility.
The below steps used to solve not allowed to use this program error.
$ crontab -e
You (oracle) are not allowed to use this program (crontab)
See crontab(1) for more information
The following files control crontab usage
Go to the root user and add oracle user to the following file:
echo oracle > /etc/cron.allow
To delete user-oracle from /etc/cron.deny file.