Sometimes Font Awesome only shows rectangle and numbers

Question

I'am using Font Awesone like this:

<link href=".../css/font-awesome.min.css" rel="stylesheet" type="text/css">

and

<span class="fa-stack fa-lg myownclass">

It works in IE, Chrome and Firefox - und sometimes in Opera. Now my customer told me, that he also not see the Icon on Firefox/Windows.

Do you have an idea what's the problem? Opera sometimes shows me the Icons, sometimes only rectangles or numbers.

Can you help me? Could it be a problem of caching?

Answer 1

All Font-Awesome icons need to be given the fa class in order to properly assign the Font-Awesome font:

<span class="fa fa-stack fa-lg myownclass">
             ^^

Unless this is being defined in your .myownclass class, the Font-Awesome font will not be active.