I get 502 and 504 error from nginx in node.js - node.js

Question

I changed the config file to increase the time and uploading size and doesn't found the php-fsm file. whenever I try to click after some time it stuck and gives 504 error and then 502 error every time.
This is my nginx.conf file.. which is located on etc/nginx/nginx.conf Please give me the solution for this issue as my project is on hold because of these things and i need to launch my web app as soon as possible.
user www-data;
worker_processes auto;
pid /run/nginx.pid;
events {
worker_connections 768;
# multi_accept on;
}
http {
##
# Basic Settings
##
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 600;
types_hash_max_size 2048;
# set client body size to 500M #
proxy_connect_timeout 600;
proxy_send_timeout 600;
proxy_read_timeout 600;
send_timeout 600;
client_header_timeout 3000;
client_body_timeout 3000;
fastcgi_read_timeout 3000;
client_max_body_size 800m;
fastcgi_buffers 8 128k;
fastcgi_buffer_size 128k;
#client_max_body_size 800M;
#client_header_timeout 3000;
#client_body_timeout 3000;
#fastcgi_read_timeout 3000;
#client_max_body_size 800m;
#fastcgi_buffers 8 128k;
#fastcgi_buffer_size 128k;
#proxy_connect_timeout 600;
#proxy_send_timeout 600;
#proxy_read_timeout 600;
#send_timeout 600;
# server_tokens off;
# server_names_hash_bucket_size 64;
# server_name_in_redirect off;
include /etc/nginx/mime.types;
default_type application/octet-stream;
##
# SSL Settings
##
ssl_protocols TLSv1 TLSv1.1 TLSv1.2; # Dropping SSLv3, ref: POODLE
ssl_prefer_server_ciphers on;
##
# Logging Settings
##
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
##
# Gzip Settings
##
gzip on;
gzip_disable "msie6";
# gzip_vary on;
# gzip_proxied any;
# gzip_comp_level 6;
# gzip_buffers 16 8k;
# gzip_http_version 1.1;
# gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;
##
# Virtual Host Configs
##
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}
#mail {
# # See sample authentication script at:
# # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
# # auth_http localhost/auth.php;
# # pop3_capabilities "TOP" "USER";
# # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
# server {
# listen localhost:110;
# protocol pop3;
# proxy on;
# }
#
# server {
# listen localhost:143;
# protocol imap;
# proxy on;
# }
#}