NGINX 502 Bad Gateway: PHP-FPM

This article discusses troubleshooting NGINX 502 Bad Gateway errors when using PHP-FPM as the backend server. Common causes of these errors include PHP-FPM not running, NGINX being unable to communicate with PHP-FPM, and PHP-FPM timing out. The article provides guidance on how to detect and resolve each issue, including checking for running processes, ensuring proper socket configuration, and adjusting timeouts in both NGINX and PHP-FPM. Additionally, the article suggests using log management services and application performance monitoring (APM) tools like Datadog to analyze logs and identify bottlenecks that may be causing 502 errors.