sampoyigi Its working fine for me here, both on the demo and locally. So this might have something to do with your changes. View your page source and check to see if the link tag href attribute is correct?
sukasem For example fa-calendar is work fa-calendar-check-o is not working give square letter. I have to link to online font awesome css to get fa-calendar-check-o to work.
sukasem Main theme, It is weird. It works when using CDN link <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css"> I even copy online css to local font-awesome.min.css and not working too.
