503 Service Temporarily Unavailable nginx/1.13.3 in docker - docker

Question

I am trying to use jwilder/nginx-proxy: alpine in order to start nginx, following is the docker run command and steps:
Step1: docker run -d -p 80:80 -p 443:443 -v /var/run/docker.sock:/tmp/docker.sock:ro --name nginx jwilder/nginx-proxy:alpine
Step2: Opened port 80 in the Security Group of ec2 instance, and trying to connect to ip:80/, but the error is as follows 503 Service Temporarily Unavailable nginx/1.13.3
docker logs says:
WARNING: /etc/nginx/dhparam/dhparam.pem was not found. A pre-generated dhparam.pem will be used for now while a new one
is being generated in the background. Once the new dhparam.pem is in place, nginx will be reloaded.
forego | starting dockergen.1 on port 5000
Generating DH parameters, 2048 bit long safe prime, generator 2
forego | starting nginx.1 on port 5100
dockergen.1 | 2017/08/14 13:45:44 Generated '/etc/nginx/conf.d/default.conf' from 4 containers
dockergen.1 | 2017/08/14 13:45:44 Running 'nginx -s reload'
dockergen.1 | 2017/08/14 13:45:44 Watching docker events
dockergen.1 | 2017/08/14 13:45:44 Contents of /etc/nginx/conf.d/default.conf did not change. Skipping notification 'nginx -s reload'
nginx.1 | ec2-xx.xx.xxx.xx..ap-xyz-5.compute.amazonaws.com xx.xxx.xxx.x - "GET / HTTP/1.1" 503 615 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.90 Safari/537.36"
nginx.1 | ec2-xx.xxx.xxxx.xxx.ap-xyz-5.compute.amazonaws.com xx.xx.xx.xxx "GET /favicon.ico HTTP/1.1" 503 615 "http://ec2-xx.xxx.xx.xx.ap-xyz-5.compute.amazonaws.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.90 Safari/537.36"

Answer 1

jwilder/nginx-proxy doesn't make a lot of sense ran alone. The script behind the magic check other containers environment variables and generate the according rules to reverse proxy from hostname from another container as defined in env var : port defined the same way to the said container & port.
The key here is "hostname from another container". Nginx won't proxy-forward you when you're trying to connect with an IP like you said.
Here's an example from jwielder/nginx's README.md from its github repository
version: '2'
services:
nginx-proxy:
image: jwilder/nginx-proxy
ports:
- "80:80"
volumes:
- /var/run/docker.sock:/tmp/docker.sock:ro
whoami:
image: jwilder/whoami
environment:
- VIRTUAL_HOST=whoami.local <================
Run this, edit your hosts file (something like sudo vim /etc/hosts) add [ec2ip] whoami.local then open your browser for http://whoami.local, that'll work just fine.