I’m running a project on Railway with three services: Next.js, NestJS, and Nginx.

I’m facing an issue where I cannot reach my Next.js server from other services using the internal URL. If I use the public URL, everything works fine, but internal connections fail.

• When I try to reach Next.js from Nginx, I get a 502 Gateway Error.

• I tested my Nginx configuration and it looks correct.

• When I curl from inside another container, the request succeeds with the public domain, but fails with the internal hostname/URL.

I’m using the official Next.js Docker template from Vercel:

https://github.com/vercel/next.js/blob/canary/examples/with-docker/Dockerfile

It seems like the Next.js container isn’t accessible internally, only externally through Railway’s public proxy.