ruby on rails - Capistrano 3 + nginx setup: 502 Bad Gateway -

i deploying app via capistrano 3 ubuntu server, deployment process goes through without issues, when load website (ip), error message 502 bad gateway.

my setup:

deploy.rb:

lock "3.8.1"  set :application, "project" set :repo_url, "git@bitbucket.org:username/project.git" set :branch, "master" set :tmp_dir, '/home/deployer/tmp'  #set :rvm_type, :user                     # defaults to: :auto #set :rvm_ruby_version, '2.4.0'      # defaults to: 'default'  # default branch :master # ask :branch, `git rev-parse --abbrev-ref head`.chomp  # default deploy_to directory /var/www/my_app_name # set :deploy_to, "/var/www/my_app_name"  # default value :format :airbrussh. # set :format, :airbrussh  # can configure airbrussh format using :format_options. # these defaults. # set :format_options, command_output: true, log_file: "log/capistrano.log", color: :auto, truncate: :auto  # default value :pty false # set :pty, true  # default value :linked_files [] # append :linked_files, "config/database.yml", "config/secrets.yml"  # default value linked_dirs [] # append :linked_dirs, "log", "tmp/pids", "tmp/cache", "tmp/sockets", "public/system"  # default value default_env {} # set :default_env, { path: "/opt/ruby/bin:$path" }  # default value keep_releases 5 set :keep_releases, 5   set(:executable_config_files, %w(   unicorn_init.sh ))  # files need symlinked other parts of # filesystem. example nginx virtualhosts, log rotation # init scripts etc. set(:symlinks, [   {     source: "nginx.conf",     link: "/etc/nginx/sites-enabled/default}"   },   {     source: "unicorn_init.sh",     link: "/etc/init.d/unicorn_#{fetch(:application)}"   },   {     source: "log_rotation",    link: "/etc/logrotate.d/#{fetch(:application)}"   },   {     source: "monit",     link: "/etc/monit/conf.d/#{fetch(:application)}.conf"   } ])    namespace :deploy   desc 'stop unicorn'   task :stop     on roles(:app)       if test("[ -f #{fetch(:unicorn_pid)} ]")         execute :kill, capture(:cat, fetch(:unicorn_pid))       end     end   end    desc 'start unicorn'   task :start     on roles(:app)       within current_path         rails_env: fetch(:rails_env)           execute :bundle, "exec unicorn -c #{fetch(:unicorn_config)} -d"         end       end     end   end    desc 'reload unicorn without killing master process'   task :reload     on roles(:app)       if test("[ -f #{fetch(:unicorn_pid)} ]")         execute :kill, '-s usr2', capture(:cat, fetch(:unicorn_pid))       else         error 'unicorn process not running'       end     end   end    desc 'restart unicorn'   task :restart   before :restart, :stop   before :restart, :start  =begin   task :setup_config     on roles(:app)       sudo "ln -nfs #{current_path}/config/nginx.conf /etc/nginx/sites-enabled/default"       sudo "ln -nfs #{current_path}/config/unicorn_init.sh /etc/init.d/unicorn_#{application}"       run "mkdir -p #{shared_path}/config"       put file.read("config/database.example.yml"), "#{shared_path}/config/database.yml"       puts "now edit config files in #{shared_path}."     end   end   after "deploy:setup", "deploy:setup_config"    task :symlink_config     on roles(:app)       run "ln -nfs #{shared_path}/config/database.yml #{release_path}/config/database.yml"     end   end   after "deploy:finalize_update", "deploy:symlink_config" =end   desc "make sure local git in sync remote."   task :check_revision     on roles(:web)       unless `git rev-parse head` == `git rev-parse origin/master`         puts "warning: head not same origin/master"         puts "run `git push` sync changes."         exit       end     end   end   before "deploy", "deploy:check_revision" end 

unicorn.rb

root = "/home/deployer/apps/project/current" working_directory root  pid "#{root}/tmp/pids/unicorn.pid"  stderr_path "#{root}/log/unicorn.log" stdout_path "#{root}/log/unicorn.log"  worker_processes integer(env['web_concurrency']) timeout 30 preload_app true  listen '/tmp/unicorn.project.sock', backlog: 64  before_fork |server, worker|   signal.trap 'term'     puts 'unicorn master intercepting term , sending myself quit instead'     process.kill 'quit', process.pid   end    defined?(activerecord::base) ,     activerecord::base.connection.disconnect! end  after_fork |server, worker|   signal.trap 'term'     puts 'unicorn worker intercepting term , doing nothing. wait master send quit'   end    defined?(activerecord::base) ,     activerecord::base.establish_connection end  # force bundler gemfile environment variable # reference capistrano "current" symlink before_exec |_|   env['bundle_gemfile'] = file.join(root, 'gemfile') end 

on server: /etc/nginx/sites-enabled/default

upstream unicorn {   server unix:/tmp/unicorn.project.sock fail_timeout=0; }  server {   listen 80 default deferred;   # server_name example.com;   root /home/deployer/apps/project/current/public;    location ^~ /assets/ {     gzip_static on;     expires max;     add_header cache-control public;   }    location ~ ^/(robots.txt|sitemap.xml.gz)/ {     root /home/deployer/apps/project/current/public;   }    try_files $uri/index.html $uri @unicorn;   location @unicorn {     proxy_set_header x-forwarded-for $proxy_add_x_forwarded_for;     proxy_set_header host $http_host;     proxy_redirect off;     proxy_pass http://unicorn;   }    error_page 500 502 503 504 /500.html;   client_max_body_size 4g;   keepalive_timeout 10; } 

error log /var/log/nginx/error.log:

2017/07/26 06:57:55 [crit] 25631#25631: *1879 connect() unix:/tmp/unicorn.project.sock failed (2: no such file or directory) while connecting upstream, client: ip, server: , request: "get /favicon.ico http/1.1", upstream: "http://unix:/tmp/unicorn.project.sock:/500.html", host: "ip", referrer: "http://ip/" 

how solve error message? checked paths, should correct, not typos etc.

also, don't miss (symlinks?) in deploy.rb "refresh" /etc/nginx/sites-enabled/default file?

thank every advance.