Node Express App Connection Issue on EC2

I'm facing a connectivity issue with my Node.js Express application hosted on an EC2 instance. I can confirm that the application is running properly on an Ubuntu server and is configured to listen on the correct port. Despite this, I am unable to access the app via the public IP as the connection is being refused. I have already attempted to adjust the Security Group settings without success.

Ideal Skills and Experience:
- Proficient in AWS EC2 management
- Strong understanding of Node.js and Express
- Experienced with Ubuntu OS
- Familiar with configuring Security Groups
- Good troubleshooting skills to identify connectivity issues