Anyone experiencing intermittent SSL / ERR_SSL_PROTOCOL_ERROR on ClickFunnels custom domains, especially Instagram iOS?

We’re trying to diagnose a strange intermittent issue with pages hosted on ClickFunnels Classic and I’d love to know whether anyone else has experienced anything similar.

We use a custom subdomain connected to ClickFunnels, e.g.:

https://go.example.com/campaign-page

A small subset of users intermittently cannot load the page. Most users can access the exact same URL normally.

Reported errors have included:

• ERR_SSL_PROTOCOL_ERROR
• “This site can’t provide a secure connection”
• “Security certificate not trusted”
• blank/reloading pages
• “page not available”

We first noticed it from users opening links through Instagram on iPhone, but we have also had at least one report outside Instagram, so we’re not sure the Instagram in-app browser is the sole cause.

A few relevant details:

• Links are always shared using the full https:// URL.
• Our public links sometimes go through a standard WordPress 302 redirect before reaching the ClickFunnels page.
• The issue has occurred on more than one ClickFunnels page/campaign.
• It is intermittent — we cannot reproduce it consistently ourselves.
• DNS appears correctly configured.
• Standard SSL checks generally show the certificate as valid.
• Meta’s Sharing Debugger can successfully scrape the domain and does not show the domain as blocked or unsafe.
• Meta support suggested checking whether the server is consistently serving the full SSL certificate chain, including intermediate certificates, particularly because Instagram’s in-app browser may behave differently from normal browsers.

What I’m trying to figure out is whether anyone else using ClickFunnels Classic/custom domains has seen:

1. Intermittent SSL/TLS failures affecting only a subset of visitors

2. Different behaviour specifically on Instagram’s iOS in-app browser

3. Issues that appeared despite normal SSL checker results

4. Problems caused by different CDN/edge locations serving different TLS/certificate behaviour

If you’ve experienced anything similar, I’d really appreciate knowing roughly when it happened, what device/browser was affected, and whether you ever identified the cause and fix.

Not looking to promote anything — just trying to see whether this is an isolated configuration issue or something other ClickFunnels users have encountered.