How to troubleshoot unresponsive QR installation

I read through the troubleshooting docs, but I'm stuck in trying to figure out why my QR installation in AWS is unresponsive. I can't access it via a browser, but I can connect via docker CLI. It's an almost clean installation (deployed just a few days ago) and the only config changed was license and S3 settings. There's no resource issues; CPU and memory look fine. I tried restarting the host as well as redeploying the containers as an attempt to test the changes here). This installation was done to replace a previously unresponsive QR environment in AWS, so before I blow it away and start over again, I'd like to root cause why it keeps breaking.

EDIT: the specific behavior we're seeing a standard ERR_CONNECTION_REFUSED in Chrome.

Any tips?

Thanks

It usually means the firewall rules or security group settings on your EC2 instance need configuring.