high

NET::ERR_CERT_AUTHORITY_INVALID

SSL certificate is not signed by a trusted Certificate Authority.

Common Causes

  1. 1Self-signed certificate in production
  2. 2Missing intermediate CA certificates
  3. 3Unknown or untrusted CA

How to Fix

Use Let's Encrypt

sudo certbot --nginx -d example.com -d www.example.com

Free, trusted SSL certificates with automatic renewal.

How ObserveOne Helps

Untrusted-certificate failures often hit only some clients. An ObserveOne check requests your endpoint from outside, with no cached intermediates, so a chain problem fails the check even while your own browser still loads the site.

Start Monitoring Free

Related Errors

ERR_SSL_PROTOCOL_ERROR

The browser cannot establish a secure SSL/TLS connection because the server and browser cannot agree on a protocol version or cipher suite.

NET::ERR_CERT_DATE_INVALID

SSL certificate has expired or is not yet valid.

ERR_SSL_VERSION_OR_CIPHER_MISMATCH

Server and browser cannot agree on SSL/TLS protocol version or cipher suite.

NET::ERR_CERT_COMMON_NAME_INVALID

Domain name doesn't match any domain in the SSL certificate.

SSL Handshake Failed

SSL/TLS handshake between client and server failed to complete.