An error occurred while a request was made by Elastic Load Balancing to another service

Question

I just set up an application load balancer(ABL) on my AWS account. The ALB is able to successfully deliver requests to the EC2s in the auto scaling group.

ALB -> TargetGroup -> AutoScalingGroup

However, I see an exclamation mark appearing next to the name of my ALB, which says An error occurred while a request was made by Elastic Load Balancing to another service.

The alarms set on the ALB also works without any problems.

I'm worrying that there's something wrong with my ALB configuration. What might cause this warning message to appear?

If you need to know more information about my configuration, just tell me. I'll try my best to let you know.

Answer 1

I faced the same issue - traffic redirects fine from load balancer to target group, but there is exclamation mark next to the name of ALB.

In my case it was due to the problem with my IAM user. It didn't have permissions to access AWS WAF Web ACL. AWS showed an error in LB description right after AWS WAF Web ACL. After adding necessary permissions error near LB name disappeared.