This guide explains the distinct causes of 502 Bad Gateway, 504 Gateway Timeout, and Connection Reset errors in Nginx reverse‑proxy setups and provides a step‑by‑step, four‑segment troubleshooting workflow with concrete log examples, shell commands, and configuration recommendations.
This article explains why Nginx reverse‑proxying to an HTTPS upstream can return a 502 Bad Gateway error when SNI is not sent, shows the relevant SSL handshake log, and provides a complete configuration example—including enabling proxy_ssl_server_name—to fix the issue and avoid reload‑related socket problems.
This article explains what a 502 Bad Gateway error means, why it is usually generated by a reverse‑proxy like nginx, and provides step‑by‑step methods to identify common causes such as backend timeouts, process crashes, and misconfigured upstream servers.
This article analyzes 502 Bad Gateway errors caused by SSL handshake failures in Nginx, presents the relevant error logs and curl output, and provides a detailed configuration example—including buffer sizes, client limits, and proxy settings—to fix the issue.
