nginxを使ってgoで書かれたWebサーバにリバースプロキシしていますが、タイトルのエラーでページが表示されません。

default.conf

server {
    listen       80;
    server_name  localhost;

    #charset koi8-r;
    #access_log  /var/log/nginx/log/host.access.log  main;

    location / {
        #root   /usr/share/nginx/html;
        #index  index.html index.htm;
        proxy_pass http://127.0.0.1:60000/;
    }

    #error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }

    # proxy the PHP scripts to Apache listening on 127.0.0.1:80
    #
    #location ~ \.php$ {
    #    proxy_pass   http://127.0.0.1;
    #}

    # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
    #
    #location ~ \.php$ {
    #    root           html;
    #    fastcgi_pass   127.0.0.1:9000;
    #    fastcgi_index  index.php;
    #    fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
    #    include        fastcgi_params;
    #}

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #    deny  all;
    #}
}

goのメイン関数

package main

import (
    "github.com/labstack/echo"
    mw "github.com/labstack/echo/middleware"
    "github.com/thoas/stats"
    "os"
)

func main() {
    e := echo.New()

    // Middleware.
    e.Use(mw.Logger())
    e.Use(mw.Recover())
    e.Use(mw.Gzip())
    s := stats.New()
    e.Use(s.Handler)

    // Index page.
    e.Index("public/")

    // Static files.
    e.Static("/js", "public/js")
    e.Static("/css", "public/css")
    e.Static("/images", "public/images")

    if port := os.Getenv("PORT"); port != "" {
        e.Run(":" + port)
    } else {
        e.Run(":3000")
    }
}

このGoのWebサーバプログラムは/var/www/html/[page-name]以下に存在します。

ローカルで確認しましたがちゃんと表示されました。
アクセスしてみると

INFO|echo|127.0.0.1 GET / 200 51.487429ms 13820
INFO|echo|127.0.0.1 GET / 200 9.556293ms 13820
INFO|echo|127.0.0.1 GET / 200 8.84661ms 13820

このようにコンソールに表示されますが、ページが表示されません。なぜ表示されないのでしょうか。

nginx.conf

user  nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}

追記 error_log

2016/02/11 04:32:39 [notice] 29316#0: signal process started
2016/02/11 04:32:45 [alert] 23756#0: worker process 29319 exited on signal 11
2016/02/11 04:32:46 [alert] 23756#0: worker process 29324 exited on signal 11
2016/02/11 07:09:02 [error] 29320#0: *241 connect() failed (111: Connection refused) while connecting to upstream, client: 192.168.10.100, server: localhost, request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:60000/", host: "192.168.10.105"

一部ですが上記にようなものがたくさん書かれていました。

サーバ側での80番ポートtcpdump結果

01:02:40.058334 IP (tos 0x0, ttl 64, id 33406, offset 0, flags [DF], proto TCP (6), length 471)
    192.168.10.100.56136 > 192.168.10.105.http: Flags [P.], cksum 0x9494 (correct), seq 1:420, ack 1, win 4117, options [nop,nop,TS val 300422591 ecr 15850679], length 419
E....~@.@. ...
d..
i.H.P..Y....X...........
........GET / HTTP/1.1
Host: 192.168.10.105
Connection: keep-alive
Cache-Control: max-age=0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.111 Safari/537.36
Accept-Encoding: gzip, deflate, sdch
Accept-Language: ja,en-US;q=0.8,en;q=0.6