title: GCP Load Balancer: 502 Server Error, "failed_to_connect_to_backend"
body: <p>I have a dockerized Go application running on two GCP instances, everything works fine when using them with their individual external IPs, but when put through the load balancer, they're either slow to answer or it answers a <strong>502</strong> server error. The health checks seems to be ok, so I really don't understand.</p>
  
  <p>In the logs, the error thrown is</p>
  
  <blockquote>
    <p>failed_to_connect_to_backend</p>
  </blockquote>
  
  <p>I've already seen other answers on this question, but none of them seems to provide an answer for my case. I cannot modify the way the application is served, so it doesn't seems to be a timeout thing.</p>