If you serve fonts files from different domains, fonts might not displayed correctly due to Cross-origin resource sharing (CORS). More info about CORS here: https://en.wikipedia.org/wiki/Cross-origin_resource_sharing

Chrome, Firefox and newer versions of Internet Explorer enforce the Cross-Origin Resource Sharing standard, and thus only render web fonts served with the appropriate “Access-Control-Allow-Origin” response header.

For example if you have more than one domain/sub-domain to show your site, fonts might not be displayed correctly in your other domains/sub-domains. This might affect Font Icons like Awesome Fonts or custom fonts hosted from your server.

Use-case:
http://www.sampledomain.com ( fonts shown correctly )
http://subdomain.sampledomain.com ( fonts not shown correctly )

To solve this issue you need to set the appropriate “Access-Control-Allow-Origin” response header.

You can modify your .htaccess file to allow fonts from another domain.

<FilesMatch "\.(ttf|otf|eot|woff|woff2)$">
    <IfModule mod_headers.c>
        Header set Access-Control-Allow-Origin "http://subdomain.sampledomain.com"
    </IfModule>
</FilesMatch>

or allow fonts from all domains ( in case you have more than one domain that is mapped to your site )

<FilesMatch "\.(ttf|otf|eot|woff|woff2)$">
    <IfModule mod_headers.c>
        Header set Access-Control-Allow-Origin "*"
    </IfModule>
</FilesMatch>

Depending on the server similar code must be configured ( e.g: for IIS7 or nginx )

More info here: http://enable-cors.org/server.html