How to fix Mixed SSL Content for website?

To fix mixed SSL content issue on your website, please download and install this plugin: https://wordpress.org/plugins/ssl-insecure-content-fixer/

Then click WP Dashboard => Settings => SSL Insecure Content => select Capture All => Save changes.

Also please add via FTP in your .htaccess file the following rules:

RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301,NE]

Then save changes, clear cache in a browser, and check results at the front-end.