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Why do icons not show in Firefox or Internet Explorer?

Firefox and Internet Explorer will not let the icon font load when your website is accessed at yourname.com while the icon fonts are loading at www.yourname.com. The hostnames need to be the same (both with or both without www). Either setup your hosting control panel to redirect yourname.com to www.yourname.com or adjust the URL’s in Settings > General to use yourname.com instead of www.yourname.com (or vice-versa, depending on your preference).