A security certificate, also called an SSL or TLS certificate, is a digital document that proves a site is who it says it is and enables an encrypted connection. It is issued by a certificate authority that browsers trust, for a particular domain name, and is valid for a limited period. Many hosts renew them automatically, which is why they are easy to forget until one fails.
Why it matters
When a certificate expires, browsers stop trusting the site and show visitors a full-page warning that the connection is not private. Most will leave. Search engines notice too, and forms, checkouts and logins stop working properly. It is one of the most common reasons a healthy site suddenly looks broken, and it tends to happen because an automatic renewal quietly failed.
| What is read | Why it matters |
|---|---|
| When it expires | Browsers warn visitors once it has. |
| Whether browsers trust it | An untrusted certificate is treated as a security problem. |
How Link Signals reports it
A report on your own site connects on the secure port, reads the certificate your site presents and records its expiry date and whether it chains to a trusted authority and matches the site’s name. A certificate that expires within 21 days is flagged as a warning, and as more urgent when a week or less remains. The same section warns when your domain registration runs out within 60 days, since losing the name would take the site and its certificate with it.
If the secure version does not load, or the certificate is not trusted, the HTTPS summary shows a problem. The next step is to add HSTS once everything is working.
Common misunderstandings
- The padlock does not mean a site is safe. It means the connection is encrypted. Spam and scams use valid certificates too.
- Free certificates are real certificates. The usual ones are short-lived and rely on automatic renewal, which is why monitoring the date is useful.
- A certificate belongs to a name. One for
example.comdoes not covershop.example.comunless it was issued for it, or as a wildcard.
See check your domain and certificate.
Questions
Does Link Signals check certificates on sites I link to?
Not for expiry. If a destination’s certificate fails, the link is reported as unreachable with a certificate problem in the reason.
Who renews it?
Usually your host or CDN. Check that the renewal is set to automatic and that the email address on the account is current.
How this counts in your LinkSignal
Your site’s own certificate is a row of its external LinkSignal, your security certificate, which counts when it has expired or is close to expiring. Whether the secure version of the site loads is a separate row, HTTPS on your site. LinkSignal is Link Signals’ own metric, worked out only from what this tool finds, and it is not connected to any search engine or third-party score.
Run a scan and find where these show up on your own site.
