Problems while setting up Nginx on AWS EC2

Error: listen EACCES: permission denied 0.0.0.0:81

• error img:
• after a search, I found the reason is that, "EC2 doesn't allow users to run a process that listens on low ports (below 1024) without root privileges."

Nginx's user must be the one that you login via SSH, normally it would be ec2-user