How to Fix Err_Cert_Authority_Invalid Permanently?

Expired or Invalid SSL Certificate

📌 Cause: The website’s SSL certificate is expired or self-signed.
✅ Fix:

• Check the SSL status using:
  👉 SSL Checker
• Renew or install a valid SSL certificate from a trusted authority (e.g., Let’s Encrypt, Cloudflare, DigiCert).

Missing Intermediate Certificates

📌 Cause: Some SSL certificates require intermediate certificates to be trusted.
✅ Fix:

• Configure the server to serve the full certificate chain.

For Nginx: Add the fullchain.pem:
nginx

ssl_certificate /etc/ssl/certs/fullchain.pem;
ssl_certificate_key /etc/ssl/private/privkey.pem;

For Apache: Use the correct SSLCertificateChainFile:
apache

SSLCertificateFile /etc/ssl/certs/fullchain.pem
SSLCertificateKeyFile /etc/ssl/private/privkey.pem

Self-Signed Certificate (Development Environment)

📌 Cause: The certificate is not issued by a trusted CA.
✅ Fix (For Local Development):

• Ignore SSL in Chrome: Type chrome://flags/#allow-insecure-localhost, enable “Allow invalid certificates for resources loaded from localhost.”

Generate a valid local SSL certificate:
sh

openssl req -x509 -newkey rsa:2048 -keyout key.pem -out cert.pem -days 365 -nodes

•  Then configure your local server to use this certificate.

Browser Cache & Date Issues

📌 Cause: Outdated cache or incorrect system date.
✅ Fix:

• Clear browser cache (Ctrl + Shift + Del).
• Check system date/time:
  • On Windows: Settings > Time & Language > Sync now
  • On Mac: System Preferences > Date & Time

Antivirus or Firewall Blocking SSL

📌 Cause: Some security software intercepts SSL connections.
✅ Fix:

• Disable HTTPS scanning in your antivirus settings.
• Try another browser or disable VPN/proxy.

Incorrect SSL Configuration on Server

📌 Cause: Incorrect SSL settings in server configuration.
✅ Fix:

• Test your SSL setup 👉 SSL Labs Test
• For Cloudflare Users: Set SSL mode to “Full (Strict)” instead of “Flexible.”