I have a Wordpress website with a GoDaddy domain being hosted on SiteGround using the nameservers. I am looking to switch to a React App which is currently running on an EC2 instance in AWS. I want to run the ec2 instance (aka the react app) on a subdomain like beta.domain.com inside SiteGround while still keeping the Wordpress website since its a part of my business. I tried creating a subdomain in SiteGround and then pointed it to my EC2 instance elastic IP (the public ipv4) using an A record but it is showing "This site can't be reached" error once I go to beta.domain.com. 

What am I doing wrong? How do I run the EC2 instance in a subdomain hosted in SiteGround?

**EDIT**

Thank you, everyone, for your help. The problem was the SSL certificate for the HTTPS. The website wasn't coming on due to the HTTPS setup on the Nginx on the EC2 instance. After I put in the details of the certificate it runs properly with just the A record.