SSL Checker (2026) - Fix Certificate Errors, Chain Issues & Mixed Content

HTTPS is a baseline expectation in 2026. When SSL/TLS is misconfigured, users see security warnings, browsers block resources, and conversions drop. The fastest path to a fix is to identify which category of SSL problem you have: expiry, hostname mismatch, incomplete chain, or mixed content.

Quick Answer

Run an SSL checker on your domain, confirm the certificate matches the hostname, ensure the intermediate chain is installed, and verify expiry and protocol support. If HTTPS works but your page shows a warning icon, you likely have mixed content (HTTP assets on an HTTPS page).

What an SSL Checker Reveals

An SSL checker typically shows certificate details (issuer, subject, SANs), expiry date, chain completeness, and which protocols/ciphers are accepted. This helps you answer: is the certificate valid for this hostname, and is it served correctly to all clients?

Common SSL Errors and Fixes

1) Certificate expired. Renew the certificate and deploy it to the correct server/load balancer. If you use a CDN, ensure the certificate is updated there too.

2) Hostname mismatch. The certificate does not include the domain you are visiting (for example, www vs apex). Fix by issuing a certificate with the correct SANs.

3) Incomplete chain. The server is missing intermediate certificates. Many clients fail validation if the chain is incomplete. Install the full chain bundle.

4) Wrong certificate on one node. In load-balanced setups, one server may still serve the old cert. Ensure all nodes are updated.

5) Mixed content. Your site loads some assets over HTTP. Update asset URLs to HTTPS and check CSP and redirects.

How to Troubleshoot Mixed Content Fast

Mixed content usually happens after migrating to HTTPS. Images, scripts, iframes, or CSS files still point to http:// URLs. Fix by updating hardcoded links in templates and ensuring your CMS outputs HTTPS URLs. Also confirm third-party embeds support HTTPS.

Check browser dev tools for “Mixed Content” warnings.
Update asset URLs to https:// or protocol-relative.
Ensure redirects send all HTTP to HTTPS.
Set HSTS only after you are confident everything is HTTPS-safe.

Recommended Next Steps

SSL issues are often connected to DNS or deployment confusion. Confirm your DNS points to the correct endpoint and verify site availability. If you recently updated DNS, use propagation tools to confirm global visibility.

Website Status Checker to confirm uptime and HTTP response behavior.
DNS Lookup to confirm A/AAAA/CNAME are correct.

FAQ

Q: Why do I see “Your connection is not private”?

A: It usually indicates an invalid certificate: expired, mismatch, incomplete chain, or a MITM proxy. An SSL checker helps identify which.

Q: What is an intermediate certificate?

A: It is part of the certificate chain between your server certificate and a trusted root. Servers must send intermediates for clients to validate properly.

Q: Does CDN SSL differ from origin SSL?

A: Yes. Many CDNs have both edge certificates and origin certificates. You must ensure both sides are configured correctly.

Q: How do I fix SSL on www and non-www?

A: Issue one certificate covering both hostnames (SANs) and set redirects consistently. Make sure DNS and server routing are correct.

Q: What is HSTS and should I enable it?

A: HSTS forces browsers to use HTTPS. Enable only after confirming your site and subdomains are fully HTTPS-ready.

Q: Can mixed content affect SEO?

A: Yes. It can degrade user trust and break page resources, leading to worse engagement and indexing signals.