Root domain gets ERR_SSL_PROTOCOL_ERROR on Vercel, but www works

Found similar posts but none helped solve my issue.

My domain which i purchased through Vercel, www.sergiomjsp.com works and reaches Vercel normally, but sergiomjsp.com (without www) always gives ERR_SSL_PROTOCOL_ERROR — This site can't provide a secure connection. When i first started testing it it was working fine the day i bought the domain and connected it to my project. But about a day later is when the problems started and it has been 48+ hours with this problem.

My domain is using Vercel nameservers:

DNS results are different for the two:

sergiomjsp.com → 18.204.152.241

www.sergiomjsp.com → 216.198.79.65 / 216.198.79.1

Vercel DNS shows ALIAS records pointing to cname.vercel-dns-017.com. I've also removed the domain from my old project and tested it on a new project, but the root domain still has the SSL error.

I'm not very knowledgeable about DNS, im trying everything the Vercel Help bot suggests and other AI agents.

Accessing it outside my wifi network works (so mobile data, i havent tried other wifis) but im worried that once fully deployed, others are going to deal with the same issue if they are on the same provider as i am (not sure if thats how it works)

As others have also done, i am rerouting my apex to me www and it still does not work.

Appreciate any insight, thanks!

The domain troubleshooting guide can help with most custom domain configuration issues. You might be able to use that guide to solve it before a human is available to help you. Then you can come back here and share the answer for bonus points.

https://vercel.com/docs/domains/troubleshooting

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Hi Sergio,

The key clue is that sergiomjsp.com and www.sergiomjsp.com are resolving to different places. A redirect from the root domain to www only helps after the browser reaches Vercel, so it will not fix ERR_SSL_PROTOCOL_ERROR if your affected network is still resolving the root domain to the wrong IP.

I’d compare the authoritative Vercel DNS answer with public DNS and the resolver on the affected network:

dig A sergiomjsp.com @ns1.vercel-dns.com +short
dig A sergiomjsp.com @ns2.vercel-dns.com +short
dig A sergiomjsp.com @1.1.1.1 +short
dig A sergiomjsp.com @8.8.8.8 +short

If the Vercel nameservers return the expected Vercel edge values but your home Wi-Fi/router still returns 18.204.152.241, then this is probably stale or rewritten DNS on that network, not an SSL certificate problem in your app. In that case I’d flush the device DNS cache, restart the router, and try a different resolver or DNS-over-HTTPS temporarily.

If @ns1.vercel-dns.com or @ns2.vercel-dns.com also returns 18.204.152.241, then check the DNS records for the domain in Vercel and remove any leftover apex/root A or ALIAS record pointing there.

One small extra check:

dig CAA sergiomjsp.com +short

CAA is less likely to be the main issue here since www works, but it’s worth ruling out while debugging SSL.

Can you share the output of the two @ns*.vercel-dns.com checks and the output from the affected Wi-Fi network?