I integrated Font Awesome 5 in a project with bootstrap 4. When I recall a font via CSS it does not work. with Font Awesome 4 the code was as follows:
#mainN
Since FontAwesome 5, you have to enable a new "searchPseudoElements" option to use FontAwesome icons this way:
See also this question: Font awesome 5 on pseudo elements and the new Font Awesome API: https://fontawesome.com/how-to-use/font-awesome-api
Additionaly, change font-family in your CSS code to
font-family: "Font Awesome 5 Regular";