Using the theme on SSL
A SSL certificate need to be installed on your server. The best is to get in touch with your hosting company if you're not familiar with this.
After the SSL certificate is running on your server there are a couple of steps to take to make the theme work correctly on https (instead of default http).
The first things is to change the home and site URL under Settings -> General. Please make sure before changing this your website is fully accessible on https, else your website will not be working anymore and these settings need to be restored via FTP.
Then please install and activate the 'Really Simple SSL' plugin, and active the SSL option within the plugin settings page.
At least some of the images that are added within the customizer (as logo image, some background images) need to be removed and re-selected in order to display the correct image path.