critical

NET::ERR_CERT_DATE_INVALID

SSL certificate has expired or is not yet valid.

Common Causes

  1. 1Certificate validity period ended
  2. 2Renewal failed
  3. 3System clock incorrect

How to Fix

Set up automatic renewal

0 0 1 * * /usr/bin/certbot renew --quiet --post-hook 'systemctl reload nginx'

Schedule automatic renewal to prevent expiration.

How ObserveOne Helps

An expired certificate fails every HTTPS request, including ObserveOne's scheduled uptime checks, so the lapse becomes an alert within minutes instead of surfacing through customer reports.

Start Monitoring Free

Related Errors

NET::ERR_CERT_AUTHORITY_INVALID

SSL certificate is not signed by a trusted Certificate Authority.

NET::ERR_CERT_COMMON_NAME_INVALID

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

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.

ERR_SSL_VERSION_OR_CIPHER_MISMATCH

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

SSL Handshake Failed

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