Custom domain returns 404 NOT_FOUND on fra1 edge despite fully valid configuration

[cuissonier]

Project: `cuissoniers-projects/caviste` (prj_SlSvR4PkveUXp9LlhjYrp8x6p9g7)

Domain: caviste.cuissonier.nl

Plan: Hobby

I’ve spent significant time debugging a 404 NOT_FOUND that occurs consistently on the `fra1` edge PoP, while everything checks out correctly via the API and dashboard:

Verified via /v9/projects API:

- `targets.production.alias` includes `caviste.cuissonier.nl`, `aliasError: null`

- Latest deployment: `readyState: READY`, `readySubstate: PROMOTED`

- `paused: false`

- `ssoProtection: null` (disabled)

- No firewall rules active (`/v1/security/firewall/config` returns empty)

- Team not suspended, billing active

Verified via /v3/now/certs API:

- Valid SSL cert for caviste.cuissonier.nl (cert_9bxJuiqNvkU81KMsf3LGlqYi), not expired, autoRenew true

Verified via DNS:

- Nameservers correctly set to Hostinger’s own (not parked)

- CNAME `caviste` → `bb95967eaaeeb718.vercel-dns-017.com`, resolving to Vercel IPs as expected

The actual symptom:

- Direct deployment URL (e.g. `caviste-p8hruhpue-cuissoniers-projects.vercel.app`, built in `sfo1`) returns `200 OK` consistently

- ALL aliases — including `caviste.cuissonier.nl`, `caviste-seven.vercel.app`, and the default `caviste-cuissoniers-projects.vercel.app` — return `404 NOT_FOUND` specifically when the request routes through the `fra1` (Frankfurt) edge PoP. Error IDs all start with `fra1::…`

This strongly suggests `fra1`'s routing table for this project/alias set is stale or never synced, while other PoPs (and the origin in `sfo1`) have the correct routing.

Things I’ve tried that did NOT fix it:

- Multiple `vercel --prod` redeploys

- Removing/re-adding the domain via dashboard

- Changing DNS target between `cname.vercel-dns.com` and the project-specific CNAME value

- Unpausing the project via API (confirmed `paused: false`)

- Disabling SSO/Deployment Protection

- Fixing domain registrar nameservers (was briefly suspected, ruled out)

Would appreciate help from a Vercel engineer to check/flush the `fra1` routing table for this project. Happy to share deployment IDs or run any diagnostic on request.

[system]

There’s another community post with 404 debugging tips that might be helpful. Please give these solutions a try and let us know how it goes.

Debugging 404 Errors

Sometimes things don’t go as expected when deploying a website. If you see a 404 on your site, that means the page or resource couldn’t be found. There are many possible causes, and the absence of something can be tricky debug if you don’t know where to look. Here are some things you can do to find the cause and fix it. Debugging Tips Check the error code If you see a mostly white screen with 404: NOT_FOUND along with a Code and and ID then you can click the blue info box below the error deta…

A human should be around soon to offer more advice. But you can also get helpful information quickly by asking v0.

[cuissonier]

I now the message is automated, but for human support: i’ve tried it all. Please assists, thanks a lot. Happy to learn.