This site can’t be reached

1. Check that the server's public IP is 13.42.232.161, that is what DNS is returning.
2. Check that the subnet's route table has a route to an Internet Gateway.
3. Check that the Security Group(s) assigned to the instance allows TCP port 80 from 0.0.0.0/0.

It appears your domain is registered with a third party and not with AWS, as well as your NS. Could you please check whether your A record is mapped with the domain name, and your security groups rule. Check your instance is on or off. You could have been reached your server limit for your instance, you can resolve this issue by requesting an increase to your EC2 service quotas.

You can also follow this link for furhter information.

https://repost.aws/questions/QUsakk012zQsmQJpFCSegJoQ/this-site-cant-be-reached-using-lightsail-with-a-wordpress-instance-and-a-route-53-domain-name