HTTP
502 Bad Gateway
The server, acting as a gateway or proxy, received an invalid response from the upstream server.
当您看到此代码时
When Nginx/Apache can't reach the application server (e.g., Gunicorn is down, upstream timeout).
如何修复
Check if the upstream server is running. Verify proxy configuration. Check for upstream timeouts.
规范
查看 RFC / 规范 →相关代码
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