NET::ERR_CERT_DATE_INVALID Solutions

This Chrome error indicates certificate date problems, either expired certificates or system clock mismatches. First, verify your computer's date and time settings are correct, as incorrect system time causes valid certificates to appear expired. Check certificate expiration using Chrome DevTools: press F12, navigate to Security tab, and click "View certificate" to see validity dates.

For expired certificates on your own website, immediately renew through your certificate authority. Most providers send expiration warnings, but these sometimes land in spam folders. Implement automated renewal using Let's Encrypt with certbot:

# Install certbot
sudo apt-get update
sudo apt-get install certbot python3-certbot-nginx

# Obtain and install certificate
sudo certbot --nginx -d example.com -d www.example.com

# Test automatic renewal
sudo certbot renew --dry-run

# Add cron job for automatic renewal
echo "0 0,12 * * * root certbot renew --quiet" | sudo tee -a /etc/crontab