nginx doesn't listen on port 80 twice?

Question

Edit: Read this, first:

Apart from the accepted answer, these errors occur when nginx is started without systemd. Kill nginx: ps -ax | grep nginx

Answer 1

I came to this issue when I config three host name on one IP.

I use a free ssl cercificate which can only sign on one hostname. So I apply three ssl certificates.

server {
    listen      443 backlog=50000;
    server_name example1.com;

server {
    listen       443;
    server_name  example2.com;

server {
    listen       443  backlog=50000;
    server_name  example3.com;

When I use nginx -t to test the config file, it shows

nginx: [emerg] duplicate listen options for 0.0.0.0:443 in /etc/nginx/conf.d/example1_https.conf:2

nginx: configuration file /etc/nginx/nginx.conf test failed

I fixed it by remove the backlog=50000 from the example3.com