502 Bad Gateway - Server Error Response Status Code
Example Use
A proxy, like Cloudflare, receives a bad response from a web server it sits in front of. The proxy than responds with a 502 error.
Common reasons for this are:
- Server crash
- Network failure
- Excessive server traffic load
- Application timeout
- Application blocked
- Improperly configured server
Official Definition
The 502 (Bad Gateway) status code indicates that the server, while acting as a gateway or proxy, received an invalid response from an inbound server it accessed while attempting to fulfill the request.
Source: RFC 7231 Section 6.6.3