PHP-FPM を使用した NGINX HTTP 502 - ただしエラー ログなし

Question

私はある問題に苦しんでいます:

次のような Nginx 設定があります:

# MANAGED BY PUPPET
server {
  listen       *:80;

  server_name  www.example.org;
  return       301 http://example.org$request_uri;
}

server {
  listen *:80;

  server_name           example.org;


  index  index.html index.htm index.php;
  access_log            /var/log/nginx/example.org.access.log combined;
  error_log             /var/log/nginx/example.org.error.log;

  location / {
    root      /var/www/example_www/htdocs;
    index     index.html index.htm index.php;
  }

  location ~ \.php$ {
    include       /etc/nginx/fastcgi.conf;

    fastcgi_pass  unix:/var/run/php-fpm/example_www-fpm.sock;
    include fastcgi.conf;
  }
}
# MANAGED BY PUPPET
server {
  listen       *:443 ssl;

  server_name  www.example.org;
  return       301 https://example.org$request_uri;

  ssl_certificate           /etc/letsencrypt/live/example.org/fullchain.pem;
  ssl_certificate_key       /etc/letsencrypt/live/example.org/privkey.pem;


}

server {
  listen       *:443 ssl;

  server_name  example.org;

  ssl_certificate           /etc/letsencrypt/live/example.org/fullchain.pem;
  ssl_certificate_key       /etc/letsencrypt/live/example.org/privkey.pem;

  index  index.html index.htm index.php;
  access_log            /var/log/nginx/ssl-example.org.access.log combined;
  error_log             /var/log/nginx/ssl-example.org.error.log;


  location / {
    root      /var/www/example_www/htdocs;
    index     index.html index.htm index.php;
  }

  location ~ \.php$ {
    include       /etc/nginx/fastcgi.conf;
    fastcgi_pass  unix:/var/run/php-fpm/example_www-fpm.sock;
  }

}

これは fpm 設定です:

[example_www]

; The address on which to accept FastCGI requests.
listen = /var/run/php-fpm/example_www-fpm.sock

; Set listen(2) backlog. A value of '-1' means unlimited.
listen.backlog = -1

; Set permissions for unix socket, if one is used. In Linux, read/write
; permissions must be set in order to allow connections from a web server. Many
; BSD-derived systems allow connections regardless of permissions.
; Default Values: user and group are set as the running user
;                 mode is set to 0666
listen.owner = www-data
listen.group = www-data
listen.mode = 0660

というファイルを開いてindex.html問題なくコンテンツを表示できますが、 を開くとHTTP 502が表示されますが、またはにindex.php行がありません。/var/log/nginx/ssl-example.org.error.log/var/log/php/php7.3-fpm

すべてのサービスが動作しています:

● nginx.service - nginx - high performance web server
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2021-01-11 15:13:48 CET; 3min 0s ago
     Docs: http://nginx.org/en/docs/
  Process: 3720 ExecStart=/usr/sbin/nginx -c /etc/nginx/nginx.conf (code=exited, status=0/SUCCESS)
 Main PID: 3721 (nginx)
    Tasks: 4 (limit: 4580)
   Memory: 4.1M
   CGroup: /system.slice/nginx.service
           ├─3721 nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf
           ├─3722 nginx: worker process
           ├─3723 nginx: worker process
           └─3724 nginx: worker process

Jan 11 15:13:48 bree systemd[1]: Starting nginx - high performance web server...
Jan 11 15:13:48 bree systemd[1]: Started nginx - high performance web server.

● php7.3-fpm.service - The PHP 7.3 FastCGI Process Manager
   Loaded: loaded (/lib/systemd/system/php7.3-fpm.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2021-01-11 14:55:30 CET; 21min ago
     Docs: man:php-fpm7.3(8)
  Process: 3631 ExecReload=/bin/kill -USR2 $MAINPID (code=exited, status=0/SUCCESS)
 Main PID: 845 (php-fpm7.3)
   Status: "Processes active: 0, idle: 15, Requests: 0, slow: 0, Traffic: 0req/sec"
    Tasks: 16 (limit: 4580)
   Memory: 45.5M
   CGroup: /system.slice/php7.3-fpm.service
           ├─ 845 php-fpm: master process (/etc/php/7.3/fpm/php-fpm.conf)
           ├─3632 php-fpm: pool example_www
           ├─3633 php-fpm: pool example_www
           ├─3634 php-fpm: pool example_www
           ├─3635 php-fpm: pool example_www
           ├─3636 php-fpm: pool example_www
           ├─3637 php-fpm: pool staging_example_www
           ├─3638 php-fpm: pool staging_example_www
           ├─3639 php-fpm: pool staging_example_www
           ├─3640 php-fpm: pool staging_example_www
           ├─3641 php-fpm: pool staging_example_www
           ├─3642 php-fpm: pool www
           ├─3643 php-fpm: pool www
           ├─3644 php-fpm: pool www
           ├─3646 php-fpm: pool www
           └─3647 php-fpm: pool www

Jan 11 14:55:29 bree systemd[1]: Starting The PHP 7.3 FastCGI Process Manager...
Jan 11 14:55:30 bree systemd[1]: Started The PHP 7.3 FastCGI Process Manager.
Jan 11 15:13:04 bree systemd[1]: Reloading The PHP 7.3 FastCGI Process Manager.
Jan 11 15:13:04 bree systemd[1]: Reloaded The PHP 7.3 FastCGI Process Manager.