While adding a cron job from cPanel, you may see an error message as
/usr/bin/crontab permissions are wrong (6755). Please set to 4755.
The reason is quite simple, the “crontab” executable have incorrect permissions as stated in the error message. The permissions of /usr/bin/crontab should be 4755.
root@server [~]# ls -la /usr/bin/crontab
-rwsr-xr-x 1 root root 208810 Jun 1 12:24 /usr/bin/crontab*
In order to set the required permissions, ssh to your server as user ‘root’ and use the the ‘chmod’ command to correct the permissions:
chmod 4755 /usr/bin/crontab
OR
chmod u+s /usr/bin/crontab
Once the permissions are corrected, you will be able to add the cronjobs from cPanel.