What the live certificate check establishes
The tool resolves public addresses and makes a validated TLS connection to port 443 with the requested hostname. A successful result confirms that the selected endpoint presented a certificate trusted by our server at the time of checking. It shows the issuer, dates, covered names and negotiated protocol. It does not certify the business or assess all website vulnerabilities.
Handle errors and expiry
A failed connection can indicate an expired certificate, hostname mismatch, missing chain, incompatible TLS or an unreachable server. A network failure alone does not prove certificate expiry. Renew approaching certificates with your host and check both the main domain and www. A CDN can serve different certificates from different locations; this checks one responding endpoint, not every edge.