Why does Elastic Load Balancing report 'Out of Service'?

Question

I am trying to set up Elastic Load Balancing (ELB) in AWS to split the requests between multiple instances. I have created several images of my webserver based on the same AMI,

Answer 1

I would like to provide you a general way to solve this problem. When you have set up you web server like apache or nginx, try to read the access log file to see what happened. In my occasion, it report 401 error because I have add the basic auth in nginx. Of course, just like @ivankoni remind, it may because of the document you check is not exist.