Unable to connect to devpi-server from a computer in the same network

Question

I have a devpi-server running at http://localhost:3141/cloud-labs/dev/+simple. It's IP is 10.75.213.161. If I do something like pip install...., it installs from this index(http://localhost:3141/xxx/xxx/+simple).

I want this server to be used by other machines in the same network. Here is /root/.pip/pip.conf (The machine I want to connect to server)

[global]
index_url = http://10.75.213.161
[search]
index = http://10.75.213.161

Here is the /etc/nginx/conf.d/default.conf on the server.

server {

    listen      0.0.0.0:3128;
    #server_name  http://localhost:443;

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

    location / {
        root   /usr/share/nginx/html;
        index  index.html index.htm;
        proxy_pass  http://localhost:3141/cloud-labs/dev/+simple;
    }
#location /route {
    #proxy_pass  http://localhost:3141/cloud-labs/dev/+simple;
#}
    #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;
    #}
}

This is the error I recieve,

Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPConnection object at 0x7f27020ca090>: Failed to establish a new connection: [Errno 111] Connection refused',)':