If you want to debug something you ALWAYS want to check your logs. There is usefull information inside here most of the time. Please post the nginx error log.

nginx error log is as below.

2016/01/18 08:12:21 [emerg] 494#0: bind() to 0.0.0.0:80 failed (98: Address already in use)
2016/01/18 08:12:21 [emerg] 494#0: bind() to [::]:80 failed (98: Address already in use)
2016/01/18 08:12:21 [emerg] 494#0: bind() to 0.0.0.0:80 failed (98: Address already in use)
2016/01/18 08:12:21 [emerg] 494#0: bind() to [::]:80 failed (98: Address already in use)
2016/01/18 08:12:21 [emerg] 494#0: bind() to 0.0.0.0:80 failed (98: Address already in use)
2016/01/18 08:12:21 [emerg] 494#0: bind() to [::]:80 failed (98: Address already in use)
2016/01/18 08:12:21 [emerg] 494#0: bind() to 0.0.0.0:80 failed (98: Address already in use)
2016/01/18 08:12:21 [emerg] 494#0: bind() to [::]:80 failed (98: Address already in use)
2016/01/18 08:12:21 [emerg] 494#0: bind() to 0.0.0.0:80 failed (98: Address already in use)
2016/01/18 08:12:21 [emerg] 494#0: bind() to [::]:80 failed (98: Address already in use)
2016/01/18 08:12:21 [emerg] 494#0: still could not bind()
2016/01/18 08:36:01 [emerg] 547#0: a duplicate default server for 0.0.0.0:80 in /etc/nginx/sites-enabled/ghost:2
2016/01/18 08:36:06 [emerg] 567#0: a duplicate default server for 0.0.0.0:80 in /etc/nginx/sites-enabled/ghost:2
2016/01/18 08:36:31 [emerg] 600#0: a duplicate default server for 0.0.0.0:80 in /etc/nginx/sites-enabled/ghost:2
2016/01/18 08:37:18 [emerg] 622#0: a duplicate default server for 0.0.0.0:80 in /etc/nginx/sites-enabled/ghost:2
2016/01/18 08:37:24 [emerg] 625#0: a duplicate default server for 0.0.0.0:80 in /etc/nginx/sites-enabled/ghost:2

And this is what inside /sites-enabled/ghost file.

server {
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;

    server_name khay.me; # Replace with your domain

    root /usr/share/nginx/html;
    index index.html index.htm;

    client_max_body_size 10G;

    location / {
        proxy_pass http://localhost:2368;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_buffering off;
    }
}

Thanks for your help

Allright, please give the output of:

grep -r listen /etc/nginx/sites-enabled/*

@CrypticDesigns

/etc/nginx/sites-enabled/arkaraung.me:        listen 80; ## listen for ipv4; this line is default and implied
/etc/nginx/sites-enabled/arkaraung.me:        #listen [::]:80 default ipv6only=on; ## listen for ipv6
/etc/nginx/sites-enabled/ghost:    listen 80 default_server;
/etc/nginx/sites-enabled/ghost:    listen [::]:80 default_server ipv6only=on;