Firefox rendering issue and SSL handshake failure on web portal
Hello Mozilla Community,
We are experiencing an issue where our legal services web portal (hdclaims.co.uk) fails to load properly specifically for users on the latest version of Firefox on desktop.
Problem / Issue:
Users report receiving a SEC_ERROR_UNKNOWN_ISSUER error when attempting to access our online claims form.
The issue does not occur in Chromium-based browsers, but Firefox blocks the websocket connection required for live chat support.
Environment Details:
Browser: Firefox Desktop (Latest Version)
Website: hdclaims.co.uk
Server Setup: Nginx reverse proxy with LetsEncrypt / Cloudflare SSL certificate.
Steps Taken:
Verified intermediate CA certificates are properly chained on the origin server.
Tested with a fresh Firefox profile (no extensions enabled), but the security warning persists intermittent for UK users.
Checked SSL Labs report, which confirms an A+ grade.
Is there a specific cipher suite requirement or OCSP stapling configuration in Firefox that could cause this intermittent SSL handshake failure on .co.uk domains?
Any insights from the community would be appreciated!
Alle Antworten (2)
If the portal works in another browser but fails in Firefox, I would first separate the rendering problem from the SSL handshake error, since they may have different causes.
For the SSL error, check the Firefox error code first. If it is something like `SSL_ERROR_HANDSHAKE_FAILURE_ALERT` or `PR_END_OF_FILE_ERROR`, the browser is failing during TLS negotiation rather than while loading the page itself. Checking the certificate, TLS version, proxy settings, and any antivirus/firewall HTTPS inspection is a good place to start.
A quick test is to open Firefox in Troubleshoot Mode. If the portal works there, an extension or custom browser setting is likely involved.
I would also compare the same portal in a fresh Firefox profile. This is useful because it rules out cached site data, modified preferences, and profile-specific configuration without changing the existing profile.
If the problem only happens on this particular portal, check whether the server requires a specific TLS configuration or has an incomplete/incorrect certificate chain. Firefox can also be stricter than some other browsers when it comes to certificate and TLS issues.
For the rendering side, inspect the browser console for JavaScript errors and the Network tab for failed CSS/JS requests. A page that loads but appears broken can simply be missing one of its scripts or stylesheets because an earlier request failed.
So I would troubleshoot it in this order:
1. Note the exact Firefox SSL error code. 2. Try Troubleshoot Mode. 3. Test with a new Firefox profile. 4. Check proxy, antivirus and HTTPS inspection settings. 5. Verify the portal's certificate chain and TLS configuration. 6. Check the browser console and Network tab for failed resources.
If it fails only in Firefox and the exact SSL error code is available, that code usually gives a much narrower starting point than the rendering symptoms alone.
ROFL Hamilton & Douglas should probably brief their "SEO" people when making up slop in chatbots to actually check with their IT first, in case they make up bogus crap that's quite easy to verify.
There might be your main issue:
Server Setup: Nginx reverse proxy with LetsEncrypt / Cloudflare SSL certificate.
Bad news: The server is not Nginx, the cert is not provided by Let's Encrypt, and it also has nothing issued from Cloudflare 🙈 ;DDDDDDDDDD 🤡
Wanna try again?
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