Are you stuck with HAProxy 502 bad gateway? We can help you in solving it.

Usually, HAProxy 502 bad gateway occurs due to firewall blocks, no connectivity to the server and so on.

At Bobcares, we often receive requests to fix this error as part of our Server Management Services.

Today, let’s discuss how our Support Engineers fix this error easily for our customers.

Causes of HAProxy 502 bad gateway

Before getting detailed on how to fix this error, let’s have a look at its main causes.

As we all know, High Availability Proxy or HAProxy is a popular load balancer that distributes the workloads across multiple servers.

But, often it throws 502 bad gateway error. This happens when the proxy server didn’t get a valid response from the origin server.

If the domain name does not resolve to the correct IP address or any IP, then a 502 error occurs.

Similarly, when the server is down or no connectivity to the server happens, it returns bad gateway error.

Also, the firewall blocking the communication between the edge servers and the origin server also causes this error.

How we fix this error?

Recently, one of our customers approached us with a 502 error. The customer had Ubuntu 12.04LTS running and was using HAProxy as a proxy server.

But, when he requested his page, he got a “502 Bad Gateway” error. Our Support Engineers checked the error in detail.

On checking, we found errors with the security plugins used in the CMS. To resolve the error, we suggested going for an alternative security plugin.

Similarly, to resolve this error, we check the reachability of the server using a ping test or trace-route.

Also, we need to DNS check whether the Fully Qualified Domain Name is resolving correctly or not.

[Need more assistance to fix this error?- We’re available 24/7.]

Conclusion

In short, the HAProxy 502 bad gateway occurs due to firewall blocks, no connectivity to the server and so on. In today’s article, we discussed how our Support Engineers resolve this error easily for our customers.