Subject: n8n + custom domain: ERR_ERL_UNEXPECTED_X_FORWARDED_FOR blocking webhooks

Hello Railway Support Team,

I’m running n8n (Docker image: n8nio/n8n) as a web service on Railway with a custom domain attached.

I’m encountering a reproducible issue where incoming webhooks (Telegram Trigger) never reach the application when a custom domain is used.

Issue description

For every incoming HTTP request (Telegram webhook), the service fails at the middleware level with the following error:

ValidationError: The 'X-Forwarded-For' header is invalid
code: ERR_ERL_UNEXPECTED_X_FORWARDED_FOR
(express-rate-limit)

As a result:

• the webhook reaches Railway,

• but does not reach n8n,

• and no executions are created in n8n.

What has been verified

• Custom domain is correctly attached and visible in Deployments

• HTTPS / SSL is active

• Service is online and publicly accessible

• Port is properly exposed

• Environment variables configured:

  • N8N_TRUST_PROXY=true

  • N8N_LISTEN_ADDRESS=0.0.0.0

  • N8N_DISABLE_RATE_LIMIT=true

  • PORT=5678, N8N_PORT=5678

• Full redeploy performed

The error persists consistently.

Important observation

When using the default *.up.railway.app domain, webhooks work correctly.

The issue occurs only when a custom domain is used, which strongly suggests an issue with how X-Forwarded-For headers are handled by the Railway proxy for custom domains.

Questions

1. Are there any known limitations or special behaviors of Railway proxy regarding X-Forwarded-For when using custom domains?

2. Is it possible to:

   • normalize or correctly forward the X-Forwarded-For header, or

   • disable or adjust this behavior for backend services?

3. Is there a recommended configuration for applications behind Railway proxy (Express / rate-limit) to avoid this error?

I can provide logs or reproduce the issue in a minimal test service if needed.

Thank you for your time and support.

Best regards,