502 Bad Gateway
The proxy got a bad response from the server behind it
Seen in nginx, load balancers, CDNs
A reverse proxy or load balancer reached your application and got an invalid response, or no response.
Common causes
- The application crashed or isn't running.
- The proxy points at the wrong upstream port or socket.
- The upstream closed the connection or returned malformed headers.
How to fix it
- Check the application is running and its logs.
- Check the proxy's upstream address and port.
- Look at the proxy error log for the exact upstream error.
Got a different message? Paste it into the error explainer.
Related errors
- 504 Gateway Timeout · The server behind the proxy took too long
- Error 520: Web server is returning an unknown error · Cloudflare got an empty or invalid response
- 429 Too Many Requests · You've hit a rate limit
- 400 Bad Request · The server could not understand the request
- 401 Unauthorized · The request needs valid credentials
- 403 Forbidden · The server refuses to allow this request
- 404 Not Found · Nothing exists at this URL
- 405 Method Not Allowed · This URL does not accept that HTTP method
- 410 Gone · The resource was removed on purpose
- 414 Request-URI Too Large · The URL is longer than the server accepts
- 500 Internal Server Error · The application hit an error it did not handle
- 400 Bad Request: The plain HTTP request was sent to HTTPS port · Plain HTTP was sent to a port that expects TLS