Add SSL (https) to a CPanel Site
After Installing the SSL certificate, (CPanels and LetsEncrypt provides free SSL Certificate), the next step is redirecting the http:// traffic to https://
Using the redirect facility will result in redirect loop, as such add the following code at the end of .htaccess file on the root of the domain
RewriteEngine On
RewriteCond %{SERVER_PORT} 80
RewriteRule ^(.*)$ https://www.yourdomain.com/$1 [R,L]
H/T to http://www.webhostinghub.com/help/learn/website/ssl/force-website-to-use-ssl