I’ve tried deactivation W3 Total Cache, Autoptimize, Far Future Expiration Plugin and all plugins which I could deactivate without loosing functionalities I need for the website.
I do not see the problem on your site, seems you disabled site preloader.
Could you please provide wp-admin access in Private Content?
Also, please try to disable all 3-rd party plugins (means the plugins that are not included in the theme package are not in the list of required plugins http://xstore.helpscoutdocs.com/article/36-included-plugins) and then check. Note that we don’t guarantee full compatibility with third-party plugins.