An SSL/TLS certificate warning means the browser or client could not establish trust in the site's HTTPS identity. Modern TLS certificates are used to authenticate the site and help encrypt traffic.
Common causes
- The certificate has expired or is not yet valid.
- The certificate does not cover the hostname being visited.
- The server is missing an intermediate certificate.
- Certificate renewal failed or DNS points to a different server.
- The device clock is substantially incorrect.
How to investigate
- Confirm the address and hostname are correct.
- Check certificate dates and the names listed on the certificate.
- Review your hosting or certificate-provider renewal status.
- Confirm DNS points to the intended service and the full certificate chain is installed.
- Renew or reinstall the certificate using your host's supported process.
Do not tell visitors to ignore certificate warnings or enter sensitive information through a connection they cannot verify.