Icons are missing from the Admin area

If you would see a screen like this:

It means, that the fonts aren't correctly set up in your server. Open up your .htaccess file, and put these codes into it:

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

Which usually solves it, but if you are not sure about yourself, or this doesn't have an effect, you should contact your server host, and ask them for help, tell them, that your fonts aren't loading correctly.