ERR_CERT_AUTHORITY_INVALID
The certificate is not trusted
What it means
The site's certificate was signed by an authority Windows does not know, so the browser cannot prove who runs the site.
Common causes
- A self-signed certificate on a local server
- A corporate proxy that signs traffic itself
- A fake site or a captive portal
How to fix it
- Check the certificate details in the browser: the issuer tells you whether it is self-signed or corporate.
- On a work network, install the company root certificate only if IT tells you to.
- For your own server, use a free certificate from Let's Encrypt instead of a self-signed one.
- Never click through the warning on a banking or login page.