NodeJS application stopping on EC2 instance

I have a NodeJS application running on a EC2 instance free-tier. There are a bunch of functions and some functions connects to an AWS RDS database. The issue I am facing is that the NodeJS application stops to work by itself, I have to connect to the console and re-start the application manually. No deployments are being made.

The app is started using nodemon index.js Any idea on how it can be prevented?

Thanks