HTTP 411 Length Required vs 502 Bad Gateway
HTTP 411 (Length Required) is a 4xx Client Error response, while 502 (Bad Gateway) is a 5xx Server Error response. 411 indicates that the server refuses to accept the request without a Content-Length header. In contrast, 502 means that the server, acting as a gateway or proxy, received an invalid response from the upstream server.
Description
The server refuses to accept the request without a Content-Length header.
When You See It
When sending a request body without specifying Content-Length.
How to Fix
Include a Content-Length header in your request.
Description
The server, acting as a gateway or proxy, received an invalid response from the upstream server.
When You See It
When Nginx/Apache can't reach the application server (e.g., Gunicorn is down, upstream timeout).
How to Fix
Check if the upstream server is running. Verify proxy configuration. Check for upstream timeouts.
Key Differences
411 is a 4xx Client Error response, while 502 is a 5xx Server Error response.
HTTP 411: The server refuses to accept the request without a Content-Length header.
HTTP 502: The server, acting as a gateway or proxy, received an invalid response from the upstream server.
You encounter 411 when when sending a request body without specifying Content-Length.
You encounter 502 when when Nginx/Apache can't reach the application server (e.g., Gunicorn is down, upstream timeout).
When to Use Which
For 411 (Length Required): Include a Content-Length header in your request. For 502 (Bad Gateway): Check if the upstream server is running. Verify proxy configuration. Check for upstream timeouts.