This should be done
Step 1: configure your configuration.php file
Open your configuration.php file
Find the following line:
var $live_site ='';
Replace with:
var $live_site = 'https://www.your-domain.com';
Next, open .htaccess file then add the following code to the bottom of the file.
RewriteEngine On
RewriteCond %{HTTPS} OFF
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}
Step 2: enable Force SSL in your Joomla site