Custom domain intermittently serves wrong edge IPs

Help
1

Current versus Expected behavior

  • Current:

    • My custom domain 47-chromo.ru sometimes resolves to 64.29.17.65 / 216.198.79.1 instead of the universal apex IP 76.76.21.21.

    • Because of this, JS chunks under _next/static/... intermittently fail with ERR_CONNECTION_CLOSED

    • HTML and CSS may partially load, depending on which IP is used.

  • Expected:

    • The domain should always resolve to 76.76.21.21 (Vercel universal apex IP) so all static assets load correctly.

Steps to reproduce / Code / Configuration

  1. Domain 47-chromo.ru is added to Vercel project and verified.

  2. NS records at registrar (Reg.ru) point to:

    ns1.vercel-dns.com
ns2.vercel-dns.com

  3. Run nslookup 47-chromo.ru or open in browser multiple times.

  4. Sometimes it resolves to:

    64.29.17.65
216.198.79.1

  5. Sometimes it resolves correctly to 76.76.21.21.

  6. JS files under _next/static/chunks/ fail when hitting the wrong IP.

Project information

Additional notes

  • Authoritative NS queries (nslookup ``47-chromo.ru`` ``ns1.vercel-dns.com) return the correct IP 76.76.21.21.

  • Recursive resolvers sometimes return legacy edge IPs 64.29.17.65 / 216.198.79.1.

  • All browser caches, OS DNS caches, and Vercel caches have been cleared.

  • Issue persists across multiple networks.

4

Hey, @sherbakovsaf! Welcome :waving_hand:

Interesting issue here! I know you posted this a few days ago, so wanted to ask if you’re still seeing this? It might be worth waiting 24-48 hours for full DNS propagation, as some resolvers cache records longer.

It is also worth flushing your local DNS cache: ipconfig /flushdns (Windows) or sudo dscacheutil -flushcache (macOS)

And maybe running a test from different networks/devices to confirm it’s not local caching.

Let us know how you get on!

5

Thanks for your reply. I’ve already tried everything you suggested:

  • Cleared local DNS cache (ipconfig /flushdns) and browser cache.

  • Cleared Vercel cache.

  • Checked on multiple networks and devices.

  • Waited more than 48 hours for DNS propagation.

It works on my phone only under VPN, but not on PC, even with the same VPN.

Can you advise a solution to ensure all resolvers return the universal apex IP?

6

I installed Cloudflare WARP and all work