I just reload the nginx service by this code - sudo service nginx reload

Check your nginx.conf file, what is the issue you are facing? Is your site not loading?

What should i check in nginx.conf?
before run service nginx reload my site was working.

Nginx.conf:

For more information on configuration, see:

* Official English Documentation: http://nginx.org/en/docs/

* Official Russian Documentation: http://nginx.org/ru/docs/

user www-data;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;

events {
worker_connections 2048;
}

http {
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;
tcp_nodelay         on;
keepalive_timeout   65;
types_hash_max_size 2048;

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

# Load modular configuration files from the /etc/nginx/conf.d directory.
# See http://nginx.org/en/docs/ngx_core_module.html#include
# for more information.
include /etc/nginx/conf.d/*.conf;

}