Hi Railway Team,

I'm experiencing a persistent 502 Bad Gateway error on my Ktor (Kotlin)

backend service. The app starts and runs successfully but Railway's proxy

cannot reach it.

## Service Details

- Framework: Ktor (Kotlin) with Netty engine

- Build: Multi-stage Dockerfile (gradle:9.1.0-jdk21 → eclipse-temurin:21-jre-alpine)

- Deployment status: Green / Active

- PORT variable: 8080 (set in Variables tab)

- Target port in Networking settings: 8080

## Deploy Logs (successful startup)

Starting Container

>>> PORT env value: 8080

>>> Starting server on port: 8080

Using system environment variables

Database connected successfully

Database tables verified

Application started in 4.579 seconds.

Responding at http://0.0.0.0:8080

## The Problem

Despite the app clearly binding to 0.0.0.0:8080 and the deployment

showing green/active status, every HTTP request to the Railway public

domain returns 502 Bad Gateway.

## What I Have Tried

- Set PORT=8080 in Variables tab

- Set target port to 8080 in Networking settings

- Deleted and regenerated public domain multiple times

- Deleted and recreated the entire project from scratch

- Removed railway.toml completely

- Cleared start command and let Dockerfile ENTRYPOINT handle it

- Changed ENTRYPOINT to exec form: ["java", "-jar", "/app/app.jar"]

- Updated application.yaml to use port: ${PORT}

Nothing has resolved the 502. The app boots perfectly every time but

Railway's edge proxy cannot route traffic to it.

## Dockerfile ENTRYPOINT

ENTRYPOINT ["java", "-jar", "/app/app.jar"]

## Application binding code (Application.kt)

val port = System.getenv("PORT")?.toIntOrNull() ?: 8080

embeddedServer(Netty, host = "0.0.0.0", port = port) {

module()

}.start(wait = true)

Please check your proxy/edge logs for my service to identify

why traffic is not being routed to the running container.

Thank you.