FontAwesome not working in Firefox - HTML

Hello Dear All !
I’m developing a HTML5 Template for themeforest. I used free fontAwesome for icons in offline css. But it’s not working in Firefox. Displaying like this:
But working with Cloudflare CDN in Firefox. So my question to envato that, may I use cloudflare cdn (Online css file) for HTML5 template for themeforest Approval.
Thanks in advance.