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SSL Errors
Troubleshooting Website SecurityHTTPS

SSL Errors

Overview

SSL errors occur when a browser cannot establish a trusted HTTPS connection with a website. HTTPS connections rely on TLS certificates issued by trusted certificate authorities. If the certificate chain is invalid or misconfigured, the browser blocks the connection to prevent potential interception or impersonation attacks.

Common Causes

  • expired TLS certificates
  • certificates issued for a different domain name
  • missing intermediate certificate chain on the server
  • server configured for HTTPS without installing a certificate
  • mixed HTTP and HTTPS resources triggering browser security warnings

How the Problem Appears

  • browser warning pages such as NET::ERR_CERT_DATE_INVALID
  • visitors unable to access the site over HTTPS
  • padlock icon missing from the browser address bar
  • search engines reporting HTTPS accessibility errors

How It Is Diagnosed

  • inspecting the certificate using the browser security panel
  • testing the TLS handshake using openssl s_client -connect domain.com:443
  • verifying certificate expiration dates
  • checking the certificate chain using SSL testing tools

Typical Fix

  • renew the TLS certificate through the certificate authority
  • install intermediate certificates required for the trust chain
  • configure the correct domain names in the certificate (SAN entries)
  • redirect HTTP traffic to HTTPS once the certificate is correctly installed
  • /insights/website-security/
  • /insights/redirect-errors/
  • /insights/domain-configuration/