Why My Website is not Secure ?
This is not the issue, When your website loads images from a different server, In Theme Options you have many sections on which has our dummy image loading from our server end Like Banner, Submit listing, Claim
Once you remove the images URLs that are coming from our server and re-upload them from your server then all will be set as https secure.
You can use Really Simple SSL plugin at your site
After activation of the plugin active, the SSL then try activation it will work fine.