ERR_CERT_AUTHORITY_INVALID on Windows
Why it happens on Windows
Corporate Windows machines trust an internal inspection CA pushed by group policy. Off the corporate network — or on a personal device — that CA is missing, so every intercepted site fails authority validation.
The fix on Windows
Check whether the certificate issuer is your employer's proxy (Zscaler, Netskope, Blue Coat). If yes, connect to the corporate VPN so the CA is installed. If not, the site is serving an incomplete chain and the fix is server-side.
Is ERR_CERT_AUTHORITY_INVALID happening on your domain?
An external SSL check builds the chain from scratch with no local trust store shortcuts, so it shows a missing intermediate that your own browser may be silently caching around.
Free, no signup. Runs from outside your network, which is the only way to tell a server fault from a local one.
If that didn't fix it
Windows has its own failure mode, but ERR_CERT_AUTHORITY_INVALID has a wider set of causes that apply everywhere. The most common one overall is: the server serves only the leaf certificate and omits the intermediate bundle.
All causes and fixes for ERR_CERT_AUTHORITY_INVALID