A configuration profile or MDM-installed root certificate on iOS can be present but not enabled, so the chain validates on other devices and fails only on the phone.
A configuration profile or MDM-installed root certificate on iOS can be present but not enabled, so the chain validates on other devices and fails only on the phone.
Settings → General → About → Certificate Trust Settings, and enable full trust for the root in question. If no profile exists, the server is missing an intermediate certificate.
iPhone has its own failure mode, but ERR_CERT_AUTHORITY_INVALID has a wider set of causes. The most common one overall is: The server serves only the leaf certificate and omits the intermediate bundle.
Concatenate the intermediate certificates after the leaf in the certificate file (fullchain, not cert) and reload the server. Desktop Chrome sometimes hides this via caching, so always confirm with an external check.
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.
A configuration profile or MDM-installed root certificate on iOS can be present but not enabled, so the chain validates on other devices and fails only on the phone.
Settings → General → About → Certificate Trust Settings, and enable full trust for the root in question. If no profile exists, the server is missing an intermediate certificate.
The browser could not build a trust path from the certificate the server sent to a root it trusts. Usually the server is serving only the leaf certificate without its intermediates, or the certificate is self-signed.