If you use google chrome, it will show http or https in the url field of at the top of the browser. If it does, then that means you have insecure items on the page.

See this article for how to fix it:

https://managewp.com/blog/wordpress-ssl-settings-and-how-to-resolve-mixed-content-warnings

If your site is not loading with ssl / https, contact your host and find out why. If you or your host didn’t change it, then it should still load https.