Your custom domain is configured to route to port 3000, but your application is listening on port 8080. Update the target port in your custom domain settings to 8080 and the 502 will resolve.

A 502 error on Railway typically means your app deployed successfully but the platform's router can't connect to it, usually because it's binding to the wrong host or port. To fix this, ensure your application's web server is explicitly configured to listen on 0.0.0.0 instead of localhost, and that it utilizes the PORT environment variable automatically provided by Railway.