Please check base_url in app/config/config.php to update it to https. If it's already https, you can ignore it and don't load the contents. If you can see the content link, please share with us.

Thank you

It is already https! Sorry, I don't understand this statement "you can ignore it and don't load the contents. If you can see the content link, please share with us."

What I tried to say is that you don't have to load insecure contents.

All the links are https, once you have https base_url. I am not sure what insecure contents are there on your site. You can try live demo, if you have such issues.

If you have not modified the item and not pasted any code in ad settings then you can share the site link so that I can see what contents are insecure.

Please update to latest version. Otherwise you can manually edit the themes/default/views/header.php and change
http://fonts.googleapis.com to https://fonts.googleapis.com

Thank you