503 Service Temporarily Unavailable

Question

Randomly (some times) when I send a post to the service I get this 503, the service is light, I don't believe it's a performance problem, probably something related to the network, but I don't know what. I'm using an alb on top of an ec2, does anyone have any troubleshooting.

~~~~this return isn't from my microservice running on ec2~~~~

<html>
      <head>
            <title>503 Service Temporarily Unavailable</title>
      </head>
      <body>
            <center>
                  <h1>503 Service Temporarily Unavailable</h1>
            </center>
      </body>
</html>

503 Service Temporarily Unavailable

```

Accepted Answer

My bad ... it was health check ... (Unfortunately it is not possible to delete this question)

Answer

Hello,

It is likely that the error message you are receiving is being sent by the Application Load Balancer.

Generally, `503 Service Unavailable server` error response code indicates that the server is not ready to handle the request.

In your case, it could mean that the targets behind the ALB are either not responding to the requests, or the ALB does not have registered targets.

You can follow this [ALB troubleshooting guide](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-troubleshooting.html) to figure out the problem.

Enabling access logs for your ALB by following this [guide](https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-access-logs.html#enable-access-logging) can help you figure out the reasons for the failure.

503 Service Temporarily Unavailable

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