The custom domain is not registered on your n8n service in Railway, which is why the edge returns its fallback page even though your DNS CNAME is correctly pointing to Railway. You need to add the domain to your service under Settings > Networking > Custom Domains in the project dashboard, then once the domain is added, Railway will show a verification TXT record to create at your DNS provider alongside the existing CNAME so a certificate can be issued.

I do not see the networking tab in the project settings

To correct my earlier message, custom domains are added on the service, not the project. Click on your n8n service within the project canvas, open its Settings tab, then scroll to the Networking section where you can add your custom domain.

Check there is no option in this image.

The screenshots show the Project Settings page, which is different from the service settings. Go back to the project canvas (the visual overview showing your services as cards), click directly on the n8n service card, and you will see a set of tabs along the top of the service panel including Deployments, Variables, Settings, and Metrics. Open that Settings tab and scroll to the Networking / Public Networking section to add your custom domain there.