EC2 Auto Scalingのヘルスチェックに失敗します。対処方法を教えてください。

AWS Technical Essentials (Japanese) Japanese live-action version ID: E-04YMDV hands-on. At the end of the content, the following error message was displayed in ELB + EC2 Auto Scaling hands-on. An instance was taken out of service in response to an ELB system health check failure.

I have read the following articles in the user guide, but I have not been able to resolve the issue. https://docs.aws.amazon.com/ja_jp/autoscaling/ec2/userguide/ts-as-healthchecks.html

I tried Solution 2 for the event "ELB system health check detects failure and instance service is stopped", but the problem could not be resolved.

I understand that I am proceeding according to the hands-on video, but I do not know how to troubleshoot, and I do not know the contents of the web application provided in the content, so I would like to contact you. rice field.

I'm sorry to trouble you, but I would appreciate it if you could tell me how to solve it. Thank you.