Почему иногда вылетает ошибка 500 NGINX?

Question

Вадим Тимошенко @PbI6A_KuT

Nginx

Почему иногда вылетает ошибка 500 NGINX?

Есть конфигурация для wordpress:

server {
  listen 80;
  server_name sitename.ru *.sitename.ru;
  return 301 https://$host$request_uri;
}

server {
  listen 443 ssl;
  server_name sitename.ru *.sitename.ru;
  ssl_certificate /etc/letsencrypt/live/sitename.ru/fullchain.pem; # managed by Certbot
  ssl_certificate_key /etc/letsencrypt/live/sitename.ru/privkey.pem; # managed by Certbot
  ssl_protocols       TLSv1 TLSv1.1 TLSv1.2;
  ssl_ciphers         HIGH:!aNULL:!MD5;

  root /var/www/html/sitename.ru; # путь к WP
  index index.php;

        gzip on; # включаем сжатие gzip
        gzip_disable "msie6";
        gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript application/javascript;

        location ~ /\. {
                deny all; # запрет для скрытых файлов
        }

        location ~* /(?:uploads|files)/.*\.php$ {
                deny all; # запрет для загруженных скриптов
        }

        location ~* ^.+\.(ogg|ogv|svg|svgz|eot|otf|woff|mp4|ttf|rss|atom|jpg|jpeg|gif|png|ico|zip|tgz|gz|rar|bz2|doc|xls|exe|ppt|tar|mid|midi|wav|bmp|rtf)$ {
                access_log off;
                log_not_found off;
                expires max; # кеширование статики
        }

        location / {
                try_files $uri $uri/ /index.php?$args; # permalinks
        }

        location ~ \.php$ {
        fastcgi_pass unix:/var/run/php/php7.2-fpm.sock;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        include fastcgi_params;
        }
}

И параметры FAST CGI:

fastcgi_param  QUERY_STRING       $query_string;
fastcgi_param  REQUEST_METHOD     $request_method;
fastcgi_param  CONTENT_TYPE       $content_type;
fastcgi_param  CONTENT_LENGTH     $content_length;
fastcgi_param  SCRIPT_NAME        $fastcgi_script_name;
fastcgi_param  REQUEST_URI        $request_uri;
fastcgi_param  DOCUMENT_URI       $document_uri;
fastcgi_param  DOCUMENT_ROOT      $document_root;
fastcgi_param  SERVER_PROTOCOL    $server_protocol;
fastcgi_param  HTTPS              $https if_not_empty;
fastcgi_param  GATEWAY_INTERFACE  CGI/1.1;
fastcgi_param  SERVER_SOFTWARE    nginx/$nginx_version;
fastcgi_param  REMOTE_ADDR        $remote_addr;
fastcgi_param  REMOTE_PORT        $remote_port;
fastcgi_param  SERVER_ADDR        $server_addr;
fastcgi_param  SERVER_PORT        $server_port;
fastcgi_param  SERVER_NAME        $server_name;
fastcgi_param  SCRIPT_FILENAME    $document_root$fastcgi_script_name;
fastcgi_param  REDIRECT_STATUS    200;

В рандомные загрузки сайта вылетает 500ая ошибка. Не пойму почему. Может что-то в конфиге у меня не так?

Конфиг NGINX вообще такой:

user www-data;
worker_processes 2;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
	worker_connections 768;
	# multi_accept on;
}

http {

	##
	# Basic Settings
	##

	sendfile on;
	tcp_nopush on;
	tcp_nodelay on;
	keepalive_timeout 65;
	types_hash_max_size 2048;
	# server_tokens off;

	server_names_hash_bucket_size 64;
	# server_name_in_redirect off;
	
	client_max_body_size 999m;	

	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_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/*;
}