HTTP 502 errors when my client makes requests to a website through a Classic Load Balancer

Question

I see HTTP 502 errors when my client makes requests to a website through a Classic Load Balancer. How can I troubleshoot this?

Answer 1

Check the instances running behind your EC2 instances. They should be active and in running state. There are two possible reasons for this error:

1. Either the load balancer is not able to able to reach the instances
2. Or the webserver is not able to reach the backend web server which displays its own 502 error message.