Basic Auth on Nginx server on Elastic Beanstalk

I am trying to set up basic auth on my elastic beanstalk instance running nodejs, however, I cannot seem to get this working. I have followed this guide Nginx Server on Amazon EC2, but http traffic is still getting through the nginx instance. I think its because the nginx server on the ec2 instance is not the one I need to be altering the virtual.conf file for. I think the nginx server is on another instance entirely, but I cant seem to find it. I think this because when I ping the Domain name for my site its IP is that of the nginx server and not my Elastic IP. Any ideas on how to configure nginx to restrict http and https traffic to my site on Elastic beanstalk?