AWS Public Certificate Issue

Hello members,

I've integrated successfully a AWS public certificate for my domain ( example.com / *.example.com ). The website is hosted in the beanstalk environment as a Laravel app.

The issue is I can see the verified certificate badge on the home page of the website but not the inside laravel application pages. It shows "Not secure" but the certificate is valid. I was added Header always set Content-Security-Policy "upgrade-insecure-requests;" rule to my .htaccess file as it needs to load the website properly under HTTPS domain otherwise, the website shows an error by not loading the .css and .js files properly. Any helps would be much appreciated.

Thanks