502 Bad Gateway

Solution: review your php is running: systemctl status php-fpm

504 Gateway Time-out

• PHP, php-fpm, php -i, PHP sessions, symfony, fastcgi_pass, sessionclean (shell script),phpsessionclean.service (systemd service), phpquery, php.ini, /var/log/php*, PECL, php --help, PHPUnit, Laravel, PHP framework, Composer, phpbrew, Xdebug, php --version, PHP Fatal error, Hello, World! (php)]
• Web server: Nginx: /etc/nginx/nginx.conf, nginx -t, Nginx logs, Nginx change log, PHP, php-fpm, Let's encrypt, Nginx directives, Reverse Proxy, Configure HTTP redirection Nginx, Return, proxy_pass (Reverse proxy), ngx_http_rewrite_module, /etc/nginx/sites-enabled/, error.log, access.log, /nginx status, AIO