Intermittent SSL handshake failures on production domain (www.policygym.co)

Help
, ,
1

We’re seeing intermittent ERR_SSL_PROTOCOL_ERROR on www.policygym.co (Vercel Hobby project, custom domain via Namecheap DNS), reproducible in-browser and independently confirmed via SSL Labs.

Evidence:
SSL Labs test (SSL Server Test (Powered by Qualys SSL Labs)) on www.policygym.co, assessed Fri 14 Aug 2026 09:57 UTC — both test servers failed:

  • 76.76.21.93 — “Unexpected failure”
  • 66.33.60.194 — “Failed to communicate with the secure server”

Browser confirmation: Chrome, same domain, same morning — www.policygym.co`` sent an invalid response. ERR_SSL_PROTOCOL_ERROR.

What I’ve already checked:

  • Deployments tab: all recent deploys show Ready, no failed builds
  • Domains tab: policygym.co and policygym.vercel.app show Valid Configuration; www.policygym.co shows a “DNS Change Recommended” warning (pre-existing, not new)
  • Certificate: Let’s Encrypt cert issued 9 Aug 2026, valid to 7 Nov, no reissue since — via CT logs
  • Vercel’s own AI support agent stated DNS/cert checks are healthy on their end and suggested network-level interference, but I’ve reproduced this via SSL Labs from outside my own network, so it doesn’t look purely local

Since this is intermittent, I don’t have a live repro at posting time, but wanted to flag it with timestamps while the evidence is fresh. Happy to provide more detail — screenshots available on request.

2

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.