amazon-ec2 - Add crontab job EC2 instance Operation not permitted

Question

I'm trying to add new job to crontab using crontab -e with root user on linux ec2 instance. However I'm getting Operation not permitted while I'm trying to save my changes. And I got same error while I'm trying to add job using any other user. Moreover I can find in /var/spool/cron/crontabs root user but I cannot find another user. Also the result of ls -l for /var/spool/cron/crontabs is -rw-r--r-- 1 root root 112 Apr 7 03:21 root

How can I add the new job without getting operation not permitted error?

标签： amazon-ec2croncron-task