I created an Instance (Windows Server 2016) within AWS and the domain URL amazon gave me as below:
ec2-10-212-103-15.us-east-2.compute.amazonaws.com
Then, to create a subdomain I went to Route53 (https://console.aws.amazon.com/route53/home#Dashboard)
Here is the picture of my configurations:

But I still cannot open http://uat.ec2-10-212-103-15.us-east-2.compute.amazonaws.com/
(Note: The IP is made-up)
What do I need more to do?
Thanks