Hello,

I’m experiencing intermittent 502 Bad Gateway errors on my backend service.

The issue occurs suddenly while the service is running normally, and the logs show this:
“error”: “connection closed unexpectedly”

## What I have confirmed so far

- Build succeeds without issues.

- Healthcheck /healthz) passes.

- Container starts normally.

- No crash logs inside the application.

- The 502 happens before the request reaches the app — nothing appears in app logs.

## Suspected issue

This looks like a gateway-to-container connection problem, possibly related to:

- Incorrect port detection by the platform

- Gateway timeout/reset

- Reverse proxy losing connection to the running container

## What I need help with

Could you please verify:

1. Which port the platform expects the container to listen on?

(Some systems override PORT env to 8080 automatically.)

2. If any gateway-level timeout or connection reset is occurring?

3. Whether the reverse proxy is successfully forwarding traffic to the container?

4. What the internal meaning of:

is on your infrastructure.

## Additional context

My backend listens on:

And logs the actual port at runtime.

Thanks in advance — any insight into why the gateway occasionally returns a 502 will be greatly appreciated.