A “mixed content” error occurs when an HTTPS page loads some resources (images, CSS, JS) over HTTP. To fix it: Ensure all URLs in HTML/CSS/JS are prefixed with https:// or use protocol-relative URLs like //example.com/.... In platforms like WordPress, install a plugin like “Really Simple SSL” to automatically update all internal links to HTTPS. Add the following redirect rule to your .htaccess file: ```perl RewriteEngine On RewriteCond %{HTTPS} !=on RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301] ``` If you use a CDN, clear its cache so changes propagate to all edge servers.