Even after a website is secured Chrome, Firefox, or whatever web browser you use may still block some of your content and say your site isn't completely secure. This is usually because of mixed secure and non secure content on your website. It could be an image or video that doesn't have a secure url. Or it could be backend code that has non secure resources in it.
This is another website security issue that we've dealt with often.
Once a secure certificate is applied to a domain name it is best to comb through every page of the website to check for mixed content. When a page is found that has mixed content on it the non secure content either needs to be updated or removed.