Let’s troubleshoot the 502 error in IIS. Bobcares, as a part of our Server Management Service offers solutions to every query that comes our way.

Troubleshooting 502 error in IIS

When IIS (Internet Information Services) encounters a “502 Bad Gateway” error, it means that a gateway or proxy server on another server sent an erroneous response to the first server. When IIS is used as a gateway or proxy to transmit requests to another server, such as an application server or backend API, it frequently results in this error.

The following steps can be used to fix an IIS “502 Bad Gateway” error:

1. Firstly, verify that the backend server—the one to which IIS forwards requests—is operational.

2. Also, verify that the backend server’s application or service is operating normally and is not having any problems.

3. A 502 error may be caused by a heavy server load or by the backend server running out of resources. So, check the CPU, memory, and disk consumption on the backend server.

4. Then make sure that the network between IIS and the backend server is working properly. This entails examining the firewall settings, DNS configuration, and network disruptions.

5. For more specific fault information, also, look through the IIS logs on the backend server as well as the proxy server. The logs may offer information about what led to the poor response.

6. IIS may time out and issue a 502 error if the backend server responds too slowly. So, examine IIS’s timeout settings and make any necessary modifications.

7. Review the proxy configuration if we’re using IIS as a reverse proxy. Also, make sure that the URL routing is proper and the setup of proxy rules is correct.

8. Make sure all proxy servers are functional and capable of correctly routing requests if we are using a load-balanced configuration with multiple proxy servers.

9. Errors might result from incorrect or incompatible HTTP compression or chunking settings. Hence, make sure that both IIS and the backend server have these settings configured consistently.

10. Review the proxy’s timeout settings if we’re using one in front of IIS (a load balancer, for example). It’s also possible that the proxy is abruptly cutting off the connection.

11. Then make sure the setup of SSL certificates is correct on IIS and the backend server.

12. Check IIS’s application pool for any problems. Also, make sure the pool is active, not overloaded with worker processes, and not experiencing any application problems.

13. Lastly, check that the setup of DNS records is proper to send requests to the appropriate servers.

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Conclusion

It’s important to keep in mind that debugging a “502 Bad Gateway” problem in IIS necessitates a systematic approach and frequently entails looking at logs, server configurations, and network elements.