SSL error when using certain networks (e.g. coffee shop wifi)

Hi I have the same problem listed here from 2 months ago - https://community.vercel.com/t/err-ssl-protocol-error-on-custom-domain/1513 but that thread is locked

When folks try to access my site (https://humanlayer.dev) from coffee shop wifi, they get an SSL error.

When they switch to tethering, things work just fine

I would expect the SSL resolution to work in both cases.

It seems like the answer in https://vercel.com/guides/resolve-err-ssl-protocol-error-with-vercel is to "just fix the network configuration". I don't have the ability to fix the network in every coffee shop, and I get people texting me or writing into our discord all the time saying "hey dex your site is down".

It's not a great look for us.

This is a pretty standard nextjs site, but I had the same issue with a previous non-nextjs site, which was just static HTML hosted on vercel with a custom domain.

In both cases, I set up a custom domain, with Porkbun -> AWS NS -> CNAME record "humanlayer.dev" to "cname.vercel-dns.com" - the certificate provisioning succeeds and most networks can load the page/cert just fine

my app is at https://vercel.com/humanlayer/marketing-page

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/projects/domains/troubleshooting

You can also use v0 to narrow down the possibilities.

It looks like humanlayer.dev is configured correctly, and I can confirm that it's working on my network.

That the issue appears on some networks but not others does point to an issue with either the ISP or the wifi network. It's possible that it's being blocked on some networks because of the .dev TLD or some other domain reputation metric.

I asked v0 for other ideas, but the info is mostly the same as what you found in the SSL error guide. You can see the response here: https://v0.dev/chat/nTachwqDmuG

Thanks for getting back to me.

I thought it was the wifi interstitial, but I was sitting next to a guy who reproduced this but then every other site they wanted to use worked fine, including things like google.com and other stuff I know is deeply baked into HSTS. No redirect, no wifi portal, just worked. Tried to go back to humanlayer.dev and things broke again. I should have tried having them hit another .dev domain to see if it's the whole TLD