What does ERR_CERT_AUTHORITY_INVALID mean?

ERR_CERT_AUTHORITY_INVALID means the browser could not build a trusted chain from the site’s certificate to a certificate authority it recognizes. This often happens with a self-signed certificate, a missing intermediate certificate, an incorrectly installed chain, or security software that replaces certificates while inspecting encrypted traffic.

Open the certificate details and confirm the issuer, hostname, validity period, and chain. Test the site with an external TLS checker from another network. If public tests show the same chain error, reinstall the certificate with the complete intermediate bundle or ask the hosting provider to repair its automated SSL installation.

If the error appears on one device only, check its date and time, operating system updates, antivirus HTTPS inspection, corporate proxy, and trusted root store. Older devices may not trust a newer certificate chain. Do not install an unknown root certificate or bypass the warning for a login, payment, or administrative page.

A development site may intentionally use a local certificate, but public visitors need a certificate from a widely trusted authority. Replace temporary or origin-only certificates before exposing the server directly. After the fix, clear any relevant proxy cache and confirm that every public hostname serves the expected chain.