What API path should Angular use in LightSail? Can't make API calls.

I've set up the Lightsail MEAN up over Https. Angular Builds and loads from /opt/bitnami/apache/htdocs and is visible on the Lightsail distribution domain e.g myapp.couldfront.net

I'm running my express API app on the same server. With simply npm start for now on port 3000.

It's not clear to me what the path I should configure Angular to make calls on: http://localhost:3000/api_paths won't work. I've changed it to https://myapp.cloudfront.net:3000/api_paths doesn't work either. Calls simply time out eventually. I already opened port 3000 on the firewall.

What should that path be?