502 Bad Gateway
Published in Networking.
The 502 status code, or Bad Gateway error, means that the server is a gateway or proxy server, and it is not receiving a valid response from the backend servers that should actually fulfill the request.
If the server in question is a reverse proxy server, such as a load balancer, here are a few things to check:
- The backend servers (where the HTTP requests are being forwarded to) are healthy
- The reverse proxy is configured properly, with the proper backends specified
- The network connection between the backend servers and reverse proxy server is healthy. If the servers can communicate on other ports, make sure that the firewall is allowing the traffic between them
- If your web application is configured to listen on a socket, ensure that the socket exists in the correct location and that it has the proper permissions