通过crontab在AWS EC2上设置cron作业

i am trying to set up a cron job on one of my EC2 instances on AWS via crontab. Doing following steps:

• Log into my server via ssh (with user ec2-user) and running crontab -l to check if any crontabs are running for existing users. There isn't any.
• Run nano crontab -e to create a new crontab file for ec2-user. File created and saved. When running crontab -l getting output no crontab file for ec2-user and obviously cron is not running.

When running ps -ef | grep cron | grep -v grep cron seem to be running ok. Output is:

root 2460 1 0 13:12 ? 00:00:00 crond

I have had a look into a few resource on the web:

• Setting Cron Job in AWS EC2 instance
• Cron jobs terminate prematurely on amazon ec2 crontab

But still not working. Seems like something is wrong when creating a crontab file for ec2-user but i cannot seem to figure out what is wrong.