a month ago
Custom domain stuck on x-railway-fallback — service works on its native domain
My service FRONT (Next.js, port 3000) serves fine on its native domain pericore.up.railway.app (HTTP 200), but a custom domain I added, ciess.pericore.app, returns 502 with header x-railway-fallback: true.
The domain shows a green checkmark in some views but Networking still displays "Cloudflare proxy detected" for ciess.pericore.app. However, the DNS is already set to DNS-only (grey cloud) in Cloudflare — verified externally: ciess.pericore.app resolves directly to jexq4s09.up.railway.app → Railway IP 69.46.46.100, Server: railway-hikari, no Cloudflare proxy in the response headers.
I've already: set the CNAME to DNS-only, removed and re-added the domain (new target each time), and redeployed the service. Still stuck on fallback. It looks like Railway has a cached "proxy detected" state that isn't refreshing.
Interestingly, my other service (an API) has custom domains on the same pericore.app zone that work perfectly — only this service's custom domains fall into fallback.
Can you force a re-verification / clear the cached proxy-detection state for ciess.pericore.app on the FRONT service? Project: [pega el nombre/ID de tu proyecto].
2 Replies
a month ago
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Status changed to Open Railway • about 1 month ago
a month ago
Try deleting cache in your Cloudflare dashboard, and/or try redeploying your application. If that doesn't work, try setting your application to listen to an arbitrary port (eg, 4100) and change the URLs to reflect that change as well, and redeploy.
https://developers.cloudflare.com/cache/how-to/purge-cache/purge-by-hostname/
a month ago
Thanks! I tried both:
Set the DNS record to DNS-only (grey cloud) in Cloudflare — confirmed externally, the domain resolves straight to Railway (Server: railway-hikari, Railway IP, no Cloudflare proxy in headers).
Changed the app to listen on an arbitrary port (4100), updated all custom domains to port 4100, and redeployed.
After the port change, the "Cloudflare proxy detected" warning disappeared and both custom domains show a green check. But they still return 502 with x-railway-fallback: true.
the service (FRONT, Next.js) works perfectly on its native domain pericore.up.railway.app (HTTP 200, serves the app) on the same deployment/port. Only its custom domains fall into fallback. Meanwhile, my other service (an API) has custom domains on the same pericore.app zone that work fine.
So the app is healthy and listening correctly — it's specifically the custom-domain routing for this service that isn't binding, even with a green check.