Public IPv4 DNS not accessible

Unless you use a purchased elastic IP which is assigned to a EC2, the. Public IPs change when you stop and start an instance.

Double check and confirm if the public IP dns name has now changed.

Hello,

As you didn't change anything on the instance directly, there might be some networking problems. The first problem you might encounter is that you have a security group, which means you cannot reach your instance. The second reason that caused this is that you have changed some settings on the VPC that do not allow any Public IPv4 DNS addresses.

Here is the link to the VPC DNS Hostnames: https://docs.aws.amazon.com/vpc/latest/userguide/vpc-dns.html

Another user also had a similar problem https://repost.aws/questions/QUHr9s-6NkQDmsjEP9M6ttWw/cannot-reach-ipv4-public-ip-or-public-dns-ipv4