Fix "Your Connection Is Not Private" Errors

This warning (NET::ERR_CERT_*) means the browser can't verify your certificate is valid for this exact connection. In rough order of likelihood:

1. Expired certificate — check the expiry date; this is the most common cause by far.
2. Domain mismatch — the certificate covers example.com but the site is loading www.example.com, or vice versa.
3. Missing intermediate certificates — the CA bundle wasn't installed, so some browsers/devices can't build the trust chain.
4. Self-signed certificate — fine for local development, always a warning in production.
5. Clock skew — the visitor's device date/time is wrong, so a valid certificate looks not-yet-valid or expired to them.
6. Outdated cached certificate — you renewed, but the old certificate is still cached at a CDN or proxy layer.

Run your domain through an SSL checker (see our Free SSL Tools) — it will usually tell you exactly which of these it is within seconds.