I have some icoomon icons and they do not work only in chrome I changed the position of the html tag to insert them and nothing, it allowed the web to use its own sources in the mozila configuration and nothing, my web is in local.
<!DOCTYPE html>
<html lang="es">
<head>
<title>example </title>
<meta charset="UTF-8">
<meta name="description" content="Un excelente lugar para los amantes de la buena comida">
<meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
<link rel="stylesheet" href="../letras.css">
<link rel="stylesheet" href="../iconos/style.css">
<link rel="stylesheet" href="../css/layout.css" type="text/css">
</head>
<body>
<header>
<h1 class="header__marca"><span class="marca__inicio">hola</span><span class="marca__medio">a</span><span class="marca__final">todos</span></h1>
<address class="telefono"><span class="icon-Contactanos"></span>
<p>Llamanos al xxxxxxxx</p>
</address>
<nav>
<ul class="nav__ul">
<li class="nav__li icon-Conocenos"><a class="nav__a" href="Conocenos.html">Conocenos</a></li>
<li class="nav__li icon-Multimedia"><a class="nav__a" href="Multimedia.html">Multimedia</a></li>
<li class="nav__li icon-Contactanos"><a class="nav__a" href="Contactanos.html">Contactanos</a></li>
<li class="nav__li icon-Preguntas"><a class="nav__a" href="Preguntas.html">Preguntas</a></li>
</ul>
</nav>
</header>
<main class="contenido" role="main">
<article>
<section class="articulo__contenido articulo__contenido--img" itemscope itemtype="http://schema.org/Product">
<div class="articulo__contenido__titulo articulo__contenido--img__titulo"><span class="icon-diamante iconos"></span></div><img srcset="../img/Exclusividad500.jpg 300w,../img/Exclusividad500.jpg 600w,../img/Exclusividad1000.jpg 1000w,../img/Exclusividad1500.jpg 1500w">
<p class="articulo__contenido__descripcion articulo__contenido--img__descripcion">Exclusividad.</p>
</section>
<section class="articulo__contenido articulo__contenido--img" itemscope itemtype="http://schema.org/Product">
<div class="articulo__contenido__titulo articulo__contenido--img__titulo"><span class="icon-comida iconos"></span></div><img srcset="../img/Exclusividad.jpg 300w,../img/Comida.jpg 600w,../img/Atencion.jpg 1000w,../img/Postres.jpg 1500w">
<p class="articulo__contenido__descripcion articulo__contenido--img__descripcion">Deliciosas Comidas.</p>
</section>
<section class="articulo__contenido articulo__contenido--img" itemscope itemtype="http://schema.org/Product">
<div class="articulo__contenido__titulo articulo__contenido--img__titulo"><span class="icon-atencion iconos"></span></div><img srcset="../img/Exclusividad.jpg 300w,../img/Comida.jpg 600w,../img/Atencion.jpg 1000w,../img/Postres.jpg 1500w">
<p class="articulo__contenido__descripcion articulo__contenido--img__descripcion">Atencion de primera.</p>
</section>
<section class="articulo__contenido articulo__contenido--img" itemscope itemtype="http://schema.org/Product">
<div class="articulo__contenido__titulo articulo__contenido--img__titulo"><span class="icon-helado iconos"></span></div><img srcset="../img/Exclusividad.jpg 300w,../img/Comida.jpg 600w,../img/Atencion.jpg 1000w,../img/Postres.jpg 1500w">
<p class="articulo__contenido__descripcion articulo__contenido--img__descripcion">Postres de otro nivel.</p>
</section>
</article>
<article>
<section class="articulo__contenido" itemscope itemtype="http://schema.org/Product">
<div class="articulo__contenido__titulo"><span class="icon-ubicacion iconos"></span>
<p>Ubicacion</p>
</div>
</section>
</article>
</main>
<aside>
</aside>
<footer class="footer">
<p class="footer__titulo">hola q hace</p>
<div class="divInfocontacto">
<address class="telefono"><span class="icon-Contactanos"></span>
<p>gggggggggggggggggggggggggggggggg</p>
</address>
<address class="correo"><span class="icon-correo"></span>
<p>ggggggggggggggggg</p>
</address>
<address class="ubicacion"><span class="icon-ubicacion">DIRECCIÓN</span>
<p>dddddddddddddddddddddddddddddddddddddddddddddddddddd</p>
</address>
</div>
</footer>
<script src="../../ecma6/conocenos.js"></script>
</body>
</html>
this is the code plus try to use the safe mode of firefox and it did not work in the same way did not load the icons
@font-face {
font-family: 'icomoon';
src: url('fonts/icomoon.eot?7ap6rt');
src: url('fonts/icomoon.eot?7ap6rt#iefix') format('embedded-opentype'),
url('fonts/icomoon.ttf?7ap6rt') format('truetype'),
url('fonts/icomoon.woff?7ap6rt') format('woff'),
url('fonts/icomoon.svg?7ap6rt#icomoon') format('svg');
font-weight: normal;
font-style: normal;
}
[class^="icon-"], [class*=" icon-"] {
/* use !important to prevent issues with browser extensions that change fonts */
font-family: 'icomoon' !important;
speak: none;
font-style: normal;
font-weight: normal;
font-variant: normal;
text-transform: none;
line-height: 1;
/* Better Font Rendering =========== */
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
}
.icon-Preguntas:before {
content: "\e901";
}
.icon-Conocenos:before {
content: "\e900";
}
.icon-Multimedia:before {
content: "\e90e";
}
.icon-Contactanos:before {
content: "\e942";
}
.icon-ubicacion:before {
content: "\e948";
}
.icon-relog:before {
content: "\e94e";
}
.icon-atencion:before {
content: "\e976";
}
.icon-comida:before {
content: "\e9a3";
}
.icon-circuloArriba:before {
content: "\ea41";
}
.icon-circuloAbajo:before {
content: "\ea43";
}
.icon-diamante:before {
content: "\e904";
}
.icon-celular:before {
content: "\e902";
}
.icon-diamond:before {
content: "\e903";
}
.icon-helado:before {
content: "\e905";
}
this is the estyle