502 Bad Gateway

The server acting as a gateway received an invalid response from the upstream server. Common with reverse proxies (nginx, Cloudflare).

Status Code502
NameBad Gateway
CategoryServer Error
MeaningThe server acting as a gateway received an invalid response from the upstream server. Common with reverse proxies (nginx, Cloudflare).

Common Causes

Backend is down — the upstream server (PHP-FPM, Node, etc.) crashed

Timeout — backend took too long to respond

Wrong proxy config — nginx pointing to wrong port

Related Status Codes

500
Internal Server Error503
Service Unavailable504
Gateway Timeout

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