Hi Marion
As you are trying to load a Font Awesome 5 icon, you must first load the FA5 icon set. To do so...
1. Disable
Font Awesome in the
General -> Typography tab of your template settings.
2. Add the following to the
Custom CSS -> Custom CSS field of your template settings...
[class^="fa-"]::before, [class*=" fa-"]::before {
font-family: "Font Awesome 5 Free";
font-weight: 900;
}
3. Add the following to the
Custom Code -> Head Custom Code field...
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.5.0/css/all.css" integrity="sha384-B4dIYHKNBt8Bc12p+WXckhzcICo0wtJAoU8YZTY5qE0Id1GSseTk6S+L3BlXeVIU" crossorigin="anonymous">
Ciaran