Website SSL Certificate Error? Common HTTPS Problems Explained

A browser’s certificate warning provides a clue about an HTTPS fault. An expired certificate, wrong hostname and incomplete trust chain have different causes. Record the exact warning and affected URL before changing DNS or SSL settings.

Check the hostname and date

Compare the requested domain, including www, with names covered by the certificate. Check validity dates. A staging certificate will not secure a public domain merely because both reach the same server. If only one device sees the error, confirm its clock and browser state before changing the website.

Find where TLS terminates

A CDN or proxy may show one certificate to visitors while the origin server uses another. Identify which connection fails. If a proxy is enabled, inspect its SSL mode and origin certificate together. Changing the mode without a suitable origin certificate can replace a warning with a redirect loop.

Review renewal and DNS

Automatic renewal can fail when domain validation cannot reach the intended server or authoritative DNS points elsewhere. Check the hosting provider’s renewal log and public DNS answer. Do not copy certificate files from another domain or weaken browser checks to hide the problem. Determine who manages renewals for both the edge and the origin.

Test affected pages

After repair, test root and www addresses, an inner page and login. Check mixed content where an HTTPS page requests resources over HTTP. A browser padlock alone does not prove forms or callbacks work. Verify important functionality from a normal visitor session.

Keep a reliable record

Document the issuer, renewal owner and expiry monitoring. If the issue began after migration, compare old and new hosting certificate setups. Retain the exact warning and timestamps so a recurring problem can be traced. Avoid disabling HTTPS for visitors as a routine workaround.

Related: HTTPS troubleshooting and redirect-loop guide.