[nginx] Dealing with nginx 400 "The plain HTTP request was sent to HTTPS port" error

Here is an example to config HTTP and HTTPS in same config block with ipv6 support. The config is tested in Ubuntu Server and NGINX/1.4.6 but this should work with all servers.

server {
    # support http and ipv6
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;

    # support https and ipv6
    listen 443 default_server ssl;
    listen [::]:443 ipv6only=on default_server ssl;

    # path to web directory
    root /path/to/example.com;
    index index.html index.htm;

    # domain or subdomain
    server_name example.com www.example.com;

    # ssl certificate
    ssl_certificate /path/to/certs/example_com-bundle.crt;
    ssl_certificate_key /path/to/certs/example_com.key;

    ssl_session_timeout 5m;

    ssl_protocols SSLv3 TLSv1 TLSv1.1 TLSv1.2;
    ssl_ciphers "HIGH:!aNULL:!MD5 or HIGH:!aNULL:!MD5:!3DES";
    ssl_prefer_server_ciphers on;
}

Don't include ssl on which may cause 400 error. The config above should work for

http://example.com

http://www.example.com

https://example.com

https://www.example.com

Hope this helps!